[php] Calculate business days

I need a method for adding "business days" in PHP. For example, Friday 12/5 + 3 business days = Wednesday 12/10.

At a minimum I need the code to understand weekends, but ideally it should account for US federal holidays as well. I'm sure I could come up with a solution by brute force if necessary, but I'm hoping there's a more elegant approach out there. Anyone?

Thanks.

I just get my function working based on Bobbin and mcgrailm code, adding some things that worked perfect to me.

function add_business_days($startdate,$buisnessdays,$holidays,$dateformat){
    $enddate = strtotime($startdate);
    $day = date('N',$enddate);
    while($buisnessdays > 0){ // compatible with 1 businessday if I'll need it
        $enddate = strtotime(date('Y-m-d',$enddate).' +1 day');
        $day = date('N',$enddate);
        if($day < 6 && !in_array(date('Y-m-d',$enddate),$holidays))$buisnessdays--;
    }
    return date($dateformat,$enddate);
}

// as a parameter in in_array function we should use endate formated to 
// compare correctly with the holidays array.

Get the number of working days without holidays between two dates :

Use example:

echo number_of_working_days('2013-12-23', '2013-12-29');

Output:

3

Function:

function number_of_working_days($from, $to) {
    $workingDays = [1, 2, 3, 4, 5]; # date format = N (1 = Monday, ...)
    $holidayDays = ['*-12-25', '*-01-01', '2013-12-23']; # variable and fixed holidays

    $from = new DateTime($from);
    $to = new DateTime($to);
    $to->modify('+1 day');
    $interval = new DateInterval('P1D');
    $periods = new DatePeriod($from, $interval, $to);

    $days = 0;
    foreach ($periods as $period) {
        if (!in_array($period->format('N'), $workingDays)) continue;
        if (in_array($period->format('Y-m-d'), $holidayDays)) continue;
        if (in_array($period->format('*-m-d'), $holidayDays)) continue;
        $days++;
    }
    return $days;
}

Here is a function for adding buisness days to a date

 function add_business_days($startdate,$buisnessdays,$holidays,$dateformat){
  $i=1;
  $dayx = strtotime($startdate);
  while($i < $buisnessdays){
   $day = date('N',$dayx);
   $date = date('Y-m-d',$dayx);
   if($day < 6 && !in_array($date,$holidays))$i++;
   $dayx = strtotime($date.' +1 day');
  }
  return date($dateformat,$dayx);
 }

 //Example
 date_default_timezone_set('Europe\London');
 $startdate = '2012-01-08';
 $holidays=array("2012-01-10");
 echo '<p>Start date: '.date('r',strtotime( $startdate));
 echo '<p>'.add_business_days($startdate,7,$holidays,'r');

Another post mentions getWorkingDays (from php.net comments and included here) but I think it breaks if you start on a Sunday and finish on a work day.

Using the following (you'll need to include the getWorkingDays function from previous post)

 date_default_timezone_set('Europe\London');
 //Example:
 $holidays = array('2012-01-10');
 $startDate = '2012-01-08';
 $endDate = '2012-01-13';
 echo getWorkingDays( $startDate,$endDate,$holidays);

Gives the result as 5 not 4

Sun, 08 Jan 2012 00:00:00 +0000 weekend
Mon, 09 Jan 2012 00:00:00 +0000
Tue, 10 Jan 2012 00:00:00 +0000 holiday
Wed, 11 Jan 2012 00:00:00 +0000
Thu, 12 Jan 2012 00:00:00 +0000
Fri, 13 Jan 2012 00:00:00 +0000 

The following function was used to generate the above.

     function get_working_days($startDate,$endDate,$holidays){
      $debug = true;
      $work = 0;
      $nowork = 0;
      $dayx = strtotime($startDate);
      $endx = strtotime($endDate);
      if($debug){
       echo '<h1>get_working_days</h1>';
       echo 'startDate: '.date('r',strtotime( $startDate)).'<br>';
       echo 'endDate: '.date('r',strtotime( $endDate)).'<br>';
       var_dump($holidays);
       echo '<p>Go to work...';
      }
      while($dayx <= $endx){
       $day = date('N',$dayx);
       $date = date('Y-m-d',$dayx);
       if($debug)echo '<br />'.date('r',$dayx).' ';
       if($day > 5 || in_array($date,$holidays)){
        $nowork++;
     if($debug){
      if($day > 5)echo 'weekend';
      else echo 'holiday';
     }
       } else $work++;
       $dayx = strtotime($date.' +1 day');
      }
      if($debug){
      echo '<p>No work: '.$nowork.'<br>';
      echo 'Work: '.$work.'<br>';
      echo 'Work + no work: '.($nowork+$work).'<br>';
      echo 'All seconds / seconds in a day: '.floatval(strtotime($endDate)-strtotime($startDate))/floatval(24*60*60);
      }
      return $work;
     }

    date_default_timezone_set('Europe\London');
     //Example:
     $holidays=array("2012-01-10");
     $startDate = '2012-01-08';
     $endDate = '2012-01-13';
//broken
     echo getWorkingDays( $startDate,$endDate,$holidays);
//works
     echo get_working_days( $startDate,$endDate,$holidays);

Bring on the holidays...

Thanks to Bobbin, mcgrailm, Tony, James Pasta and a few others who posted here. I had written my own function to add business days to a date, but modified it with some code I found here. This will handle the start date being on a weekend/holiday. This will also handle business hours. I added some comments and break up the code to make it easier to read.

<?php
function count_business_days($date, $days, $holidays) {
    $date = strtotime($date);

    for ($i = 1; $i <= intval($days); $i++) { //Loops each day count

        //First, find the next available weekday because this might be a weekend/holiday
        while (date('N', $date) >= 6 || in_array(date('Y-m-d', $date), $holidays)){
            $date = strtotime(date('Y-m-d',$date).' +1 day');
        }

        //Now that we know we have a business day, add 1 day to it
        $date = strtotime(date('Y-m-d',$date).' +1 day');

        //If this day that was previously added falls on a weekend/holiday, then find the next business day
        while (date('N', $date) >= 6 || in_array(date('Y-m-d', $date), $holidays)){
            $date = strtotime(date('Y-m-d',$date).' +1 day');
        }
    }
    return date('Y-m-d', $date);
}

//Also add in the code from Tony and James Pasta to handle holidays...

function getNationalAmericanHolidays($year) {
$bankHolidays = array(
    'New Years Day' => $year . "-01-01",
    'Martin Luther King Jr Birthday' => "". date("Y-m-d",strtotime("third Monday of January " . $year) ),
    'Washingtons Birthday' => "". date("Y-m-d",strtotime("third Monday of February " . $year) ),
    'Memorial Day' => "". date("Y-m-d",strtotime("last Monday of May " . $year) ),
    'Independance Day' => $year . "-07-04",
    'Labor Day' => "". date("Y-m-d",strtotime("first Monday of September " . $year) ),
    'Columbus Day' => "". date("Y-m-d",strtotime("second Monday of October " . $year) ),
    'Veterans Day' => $year . "-11-11",
    'Thanksgiving Day' => "". date("Y-m-d",strtotime("fourth Thursday of November " . $year) ),
    'Christmas Day' => $year . "-12-25"
);
return $bankHolidays;

}

//Now to call it... since we're working with business days, we should
//also be working with business hours so check if it's after 5 PM
//and go to the next day if necessary.

//Go to next day if after 5 pm (5 pm = 17)
if (date(G) >= 17) {
    $start_date = date("Y-m-d", strtotime("+ 1 day")); //Tomorrow
} else {
    $start_date = date("Y-m-d"); //Today
}

//Get the holidays for the current year and also for the next year
$this_year = getNationalAmericanHolidays(date('Y'));
$next_year = getNationalAmericanHolidays(date('Y', strtotime("+12 months")));
$holidays = array_merge($this_year, $next_year);

//The number of days to count
$days_count = 10;

echo count_business_days($start_date, $days_count, $holidays);

?>

Here is another solution without for loop for each day.

$from = new DateTime($first_date);
$to = new DateTime($second_date);

$to->modify('+1 day');
$interval = $from->diff($to);
$days = $interval->format('%a');

$extra_days = fmod($days, 7);
$workdays = ( ( $days - $extra_days ) / 7 ) * 5;

$first_day = date('N', strtotime($first_date));
$last_day = date('N', strtotime("1 day", strtotime($second_date)));
$extra = 0;
if($first_day > $last_day) {
   if($first_day == 7) {
       $first_day = 6;
   }

   $extra = (6 - $first_day) + ($last_day - 1);
   if($extra < 0) {
       $extra = $extra * -1;
   }
}
if($last_day > $first_day) {
    $extra = $last_day - $first_day;
}
$days = $workdays + $extra

function get_business_days_forward_from_date($num_days, $start_date='', $rtn_fmt='Y-m-d') {

// $start_date will default to today    

if ($start_date=='') { $start_date = date("Y-m-d"); }

$business_day_ct = 0;

$max_days = 10000 + $num_days;  // to avoid any possibility of an infinite loop


// define holidays, this currently only goes to 2012 because, well, you know... ;-)
// if the world is still here after that, you can find more at
// http://www.opm.gov/Operating_Status_Schedules/fedhol/2013.asp
// always add holidays in order, because the iteration will stop when the holiday is > date being tested

$fed_holidays=array(
    "2010-01-01",
    "2010-01-18",
    "2010-02-15",
    "2010-05-31",
    "2010-07-05",
    "2010-09-06",
    "2010-10-11",
    "2010-11-11",
    "2010-11-25",
    "2010-12-24",

    "2010-12-31",
    "2011-01-17",
    "2011-02-21",
    "2011-05-30",
    "2011-07-04",
    "2011-09-05",
    "2011-10-10",
    "2011-11-11",
    "2011-11-24",
    "2011-12-26",

    "2012-01-02",
    "2012-01-16",
    "2012-02-20",
    "2012-05-28",
    "2012-07-04",
    "2012-09-03",
    "2012-10-08",
    "2012-11-12",
    "2012-11-22",
    "2012-12-25",
    );

$curr_date_ymd = date('Y-m-d', strtotime($start_date));    

for ($x=1;$x<$max_days;$x++)
{
    if (intval($num_days)==intval($business_day_ct)) { return(date($rtn_fmt, strtotime($curr_date_ymd))); }  // date found - return

    // get next day to check

    $curr_date_ymd = date('Y-m-d', (strtotime($start_date)+($x * 86400)));   // add 1 day to the current date

    $is_business_day = 1;

    // check if this is a weekend   1 (for Monday) through 7 (for Sunday)

    if ( intval(date("N",strtotime($curr_date_ymd))) > 5) { $is_business_day = 0; }

    //check for holiday
    foreach($fed_holidays as $holiday)
    {
        if (strtotime($holiday)==strtotime($curr_date_ymd))  // holiday found
        {
            $is_business_day = 0;
            break 1;
        }

        if (strtotime($holiday)>strtotime($curr_date_ymd)) { break 1; }  // past date, stop searching (always add holidays in order)


    }

    $business_day_ct = $business_day_ct + $is_business_day;  // increment if this is a business day

} 

// if we get here, you are hosed
return ("ERROR");

}

This code snippet is very easy to calculate business day without week end and holidays:

function getWorkingDays($startDate,$endDate,$offdays,$holidays){
$endDate = strtotime($endDate);
$startDate = strtotime($startDate);
$days = ($endDate - $startDate) / 86400 + 1;
$counter=0;
for ($i = 1; $i <= $days; $i++) {
    $the_first_day_of_week = date("N", $startDate);
    $startDate+=86400;
if (!in_array($the_first_day_of_week, $offdays) && !in_array(date("Y-m-
d",$startDate), $holidays)) {
$counter++;
}

}   
return $counter;
}
//example to use
$holidays=array("2017-07-03","2017-07-20");
$offdays=array(5,6);//weekend days Monday=1 .... Sunday=7
echo getWorkingDays("2017-01-01","2017-12-31",$offdays,$holidays)

Just finished writing an API that can be used to manipulate business days (none of these solutions quite worked for my situation :-); linking to it here in case anyone else finds it useful.

~ Nate

PHP Class to Calculate Business Days

Here is a function for adding buisness days to a date

 function add_business_days($startdate,$buisnessdays,$holidays,$dateformat){
  $i=1;
  $dayx = strtotime($startdate);
  while($i < $buisnessdays){
   $day = date('N',$dayx);
   $date = date('Y-m-d',$dayx);
   if($day < 6 && !in_array($date,$holidays))$i++;
   $dayx = strtotime($date.' +1 day');
  }
  return date($dateformat,$dayx);
 }

 //Example
 date_default_timezone_set('Europe\London');
 $startdate = '2012-01-08';
 $holidays=array("2012-01-10");
 echo '<p>Start date: '.date('r',strtotime( $startdate));
 echo '<p>'.add_business_days($startdate,7,$holidays,'r');

Another post mentions getWorkingDays (from php.net comments and included here) but I think it breaks if you start on a Sunday and finish on a work day.

Using the following (you'll need to include the getWorkingDays function from previous post)

 date_default_timezone_set('Europe\London');
 //Example:
 $holidays = array('2012-01-10');
 $startDate = '2012-01-08';
 $endDate = '2012-01-13';
 echo getWorkingDays( $startDate,$endDate,$holidays);

Gives the result as 5 not 4

Sun, 08 Jan 2012 00:00:00 +0000 weekend
Mon, 09 Jan 2012 00:00:00 +0000
Tue, 10 Jan 2012 00:00:00 +0000 holiday
Wed, 11 Jan 2012 00:00:00 +0000
Thu, 12 Jan 2012 00:00:00 +0000
Fri, 13 Jan 2012 00:00:00 +0000 

The following function was used to generate the above.

     function get_working_days($startDate,$endDate,$holidays){
      $debug = true;
      $work = 0;
      $nowork = 0;
      $dayx = strtotime($startDate);
      $endx = strtotime($endDate);
      if($debug){
       echo '<h1>get_working_days</h1>';
       echo 'startDate: '.date('r',strtotime( $startDate)).'<br>';
       echo 'endDate: '.date('r',strtotime( $endDate)).'<br>';
       var_dump($holidays);
       echo '<p>Go to work...';
      }
      while($dayx <= $endx){
       $day = date('N',$dayx);
       $date = date('Y-m-d',$dayx);
       if($debug)echo '<br />'.date('r',$dayx).' ';
       if($day > 5 || in_array($date,$holidays)){
        $nowork++;
     if($debug){
      if($day > 5)echo 'weekend';
      else echo 'holiday';
     }
       } else $work++;
       $dayx = strtotime($date.' +1 day');
      }
      if($debug){
      echo '<p>No work: '.$nowork.'<br>';
      echo 'Work: '.$work.'<br>';
      echo 'Work + no work: '.($nowork+$work).'<br>';
      echo 'All seconds / seconds in a day: '.floatval(strtotime($endDate)-strtotime($startDate))/floatval(24*60*60);
      }
      return $work;
     }

    date_default_timezone_set('Europe\London');
     //Example:
     $holidays=array("2012-01-10");
     $startDate = '2012-01-08';
     $endDate = '2012-01-13';
//broken
     echo getWorkingDays( $startDate,$endDate,$holidays);
//works
     echo get_working_days( $startDate,$endDate,$holidays);

Bring on the holidays...

I had this same need i started with bobbin's first example and ended up with this

  function add_business_days($startdate,$buisnessdays,$holidays=array(),$dateformat){
    $enddate = strtotime($startdate);
    $day = date('N',$enddate);
    while($buisnessdays > 1){
        $enddate = strtotime(date('Y-m-d',$enddate).' +1 day');
        $day = date('N',$enddate);
        if($day < 6 && !in_array($enddate,$holidays))$buisnessdays--;
    }
    return date($dateformat,$enddate);
  }

hth someone

<?php
// $today is the UNIX timestamp for today's date
$today = time();
echo "<strong>Today is (ORDER DATE): " . '<font color="red">' . date('l, F j, Y', $today) . "</font></strong><br/><br/>";

//The numerical representation for day of week (Ex. 01 for Monday .... 07 for Sunday
$today_numerical = date("N",$today);

//leadtime_days holds the numeric value for the number of business days 
$leadtime_days = $_POST["leadtime"];

//leadtime is the adjusted date for shipdate
$shipdate = time();

while ($leadtime_days > 0) 
{
 if ($today_numerical != 5 && $today_numerical != 6)
 {
  $shipdate = $shipdate + (60*60*24);
  $today_numerical = date("N",$shipdate);
  $leadtime_days --;
 }
 else
  $shipdate = $shipdate + (60*60*24);
  $today_numerical = date("N",$shipdate);
}

echo '<strong>Estimated Ship date: ' . '<font color="green">' . date('l, F j, Y', $shipdate) . "</font></strong>";
?>

function get_business_days_forward_from_date($num_days, $start_date='', $rtn_fmt='Y-m-d') {

// $start_date will default to today    

if ($start_date=='') { $start_date = date("Y-m-d"); }

$business_day_ct = 0;

$max_days = 10000 + $num_days;  // to avoid any possibility of an infinite loop


// define holidays, this currently only goes to 2012 because, well, you know... ;-)
// if the world is still here after that, you can find more at
// http://www.opm.gov/Operating_Status_Schedules/fedhol/2013.asp
// always add holidays in order, because the iteration will stop when the holiday is > date being tested

$fed_holidays=array(
    "2010-01-01",
    "2010-01-18",
    "2010-02-15",
    "2010-05-31",
    "2010-07-05",
    "2010-09-06",
    "2010-10-11",
    "2010-11-11",
    "2010-11-25",
    "2010-12-24",

    "2010-12-31",
    "2011-01-17",
    "2011-02-21",
    "2011-05-30",
    "2011-07-04",
    "2011-09-05",
    "2011-10-10",
    "2011-11-11",
    "2011-11-24",
    "2011-12-26",

    "2012-01-02",
    "2012-01-16",
    "2012-02-20",
    "2012-05-28",
    "2012-07-04",
    "2012-09-03",
    "2012-10-08",
    "2012-11-12",
    "2012-11-22",
    "2012-12-25",
    );

$curr_date_ymd = date('Y-m-d', strtotime($start_date));    

for ($x=1;$x<$max_days;$x++)
{
    if (intval($num_days)==intval($business_day_ct)) { return(date($rtn_fmt, strtotime($curr_date_ymd))); }  // date found - return

    // get next day to check

    $curr_date_ymd = date('Y-m-d', (strtotime($start_date)+($x * 86400)));   // add 1 day to the current date

    $is_business_day = 1;

    // check if this is a weekend   1 (for Monday) through 7 (for Sunday)

    if ( intval(date("N",strtotime($curr_date_ymd))) > 5) { $is_business_day = 0; }

    //check for holiday
    foreach($fed_holidays as $holiday)
    {
        if (strtotime($holiday)==strtotime($curr_date_ymd))  // holiday found
        {
            $is_business_day = 0;
            break 1;
        }

        if (strtotime($holiday)>strtotime($curr_date_ymd)) { break 1; }  // past date, stop searching (always add holidays in order)


    }

    $business_day_ct = $business_day_ct + $is_business_day;  // increment if this is a business day

} 

// if we get here, you are hosed
return ("ERROR");

}

$startDate = new DateTime( '2013-04-01' );    //intialize start date
$endDate = new DateTime( '2013-04-30' );    //initialize end date
$holiday = array('2013-04-11','2013-04-25');  //this is assumed list of holiday
$interval = new DateInterval('P1D');    // set the interval as 1 day
$daterange = new DatePeriod($startDate, $interval ,$endDate);
foreach($daterange as $date){
if($date->format("N") <6 AND !in_array($date->format("Y-m-d"),$holiday))
$result[] = $date->format("Y-m-d");
}
echo "<pre>";print_r($result);

I know I'm late to the party, but I use this old set of functions by Marcos J. Montes for figuring out holidays and business days. He took the time to add an algorithm from 1876 for Easter and he added all the major US holidays. This can easily be updated for other countries.

//Usage
$days = 30;
$next_working_date = nextWorkingDay($days, $somedate);

//add date function
function DateAdd($interval, $number, $date) {

    $date_time_array = getdate($date);
    //die(print_r($date_time_array));

    $hours = $date_time_array["hours"];
    $minutes = $date_time_array["minutes"];
    $seconds = $date_time_array["seconds"];
    $month = $date_time_array["mon"];
    $day = $date_time_array["mday"];
    $year = $date_time_array["year"];

    switch ($interval) {

        case "yyyy":
            $year+=$number;
            break;
        case "q":
            $year+=($number*3);
            break;
        case "m":
            $month+=$number;
            break;
        case "y":
        case "d":
        case "w":
            $day+=$number;
            break;
        case "ww":
            $day+=($number*7);
            break;
        case "h":
            $hours+=$number;
            break;
        case "n":
            $minutes+=$number;
            break;
        case "s":
            $seconds+=$number; 
            break;            
    }
    //      echo "day:" . $day;
    $timestamp= mktime($hours,$minutes,$seconds,$month,$day,$year);
    return $timestamp;
}

// the following function get_holiday() is based on the work done by
// Marcos J. Montes
function get_holiday($year, $month, $day_of_week, $week="") {
    if ( (($week != "") && (($week > 5) || ($week < 1))) || ($day_of_week > 6) || ($day_of_week < 0) ) {
        // $day_of_week must be between 0 and 6 (Sun=0, ... Sat=6); $week must be between 1 and 5
        return FALSE;
    } else {
        if (!$week || ($week == "")) {
            $lastday = date("t", mktime(0,0,0,$month,1,$year));
            $temp = (date("w",mktime(0,0,0,$month,$lastday,$year)) - $day_of_week) % 7;
        } else {
            $temp = ($day_of_week - date("w",mktime(0,0,0,$month,1,$year))) % 7;
        }

        if ($temp < 0) {
            $temp += 7;
        }

        if (!$week || ($week == "")) {
            $day = $lastday - $temp;
        } else {
            $day = (7 * $week) - 6 + $temp;
        }
        //echo $year.", ".$month.", ".$day . "<br><br>";
        return format_date($year, $month, $day);
    }
}

function observed_day($year, $month, $day) {
    // sat -> fri & sun -> mon, any exceptions?
    //
    // should check $lastday for bumping forward and $firstday for bumping back,
    // although New Year's & Easter look to be the only holidays that potentially
    // move to a different month, and both are accounted for.

    $dow = date("w", mktime(0, 0, 0, $month, $day, $year));

    if ($dow == 0) {
        $dow = $day + 1;
    } elseif ($dow == 6) {
        if (($month == 1) && ($day == 1)) {    // New Year's on a Saturday
            $year--;
            $month = 12;
            $dow = 31;
        } else {
            $dow = $day - 1;
        }
    } else {
        $dow = $day;
    }

    return format_date($year, $month, $dow);
}

function calculate_easter($y) {
    // In the text below, 'intval($var1/$var2)' represents an integer division neglecting
    // the remainder, while % is division keeping only the remainder. So 30/7=4, and 30%7=2
//
    // This algorithm is from Practical Astronomy With Your Calculator, 2nd Edition by Peter
    // Duffett-Smith. It was originally from Butcher's Ecclesiastical Calendar, published in
    // 1876. This algorithm has also been published in the 1922 book General Astronomy by
    // Spencer Jones; in The Journal of the British Astronomical Association (Vol.88, page
    // 91, December 1977); and in Astronomical Algorithms (1991) by Jean Meeus. 

    $a = $y%19;
    $b = intval($y/100);
    $c = $y%100;
    $d = intval($b/4);
    $e = $b%4;
    $f = intval(($b+8)/25);
    $g = intval(($b-$f+1)/3);
    $h = (19*$a+$b-$d-$g+15)%30;
    $i = intval($c/4);
    $k = $c%4;
    $l = (32+2*$e+2*$i-$h-$k)%7;
    $m = intval(($a+11*$h+22*$l)/451);
    $p = ($h+$l-7*$m+114)%31;
    $EasterMonth = intval(($h+$l-7*$m+114)/31);    // [3 = March, 4 = April]
    $EasterDay = $p+1;    // (day in Easter Month)

    return format_date($y, $EasterMonth, $EasterDay);
}


function nextWorkingDay($number_days, $start_date = "") {
    $day_counter = 0;
    $intCounter = 0;    

    if ($start_date=="") {
        $today  = mktime(0, 0, 0, date("m")  , date("d"), date("Y"));
    } else {
        $start_time = strtotime($start_date);
        $today  = mktime(0, 0, 0, date("m", $start_time)  , date("d", $start_time), date("Y", $start_time));
    }

    while($day_counter < $number_days) {
        $working_time = DateAdd("d", 1, $today);
        $working_date = date("Y-m-d", $working_date);
        if (!isWeekend($working_date) && !confirm_holiday(date("Y-m-d", strtotime($working_date))) ) {
            $day_counter++;
        }
        $intCounter++;
        $today  = $working_time;
        if ($intCounter > 1000) {
            //just in case out of control?
            break;
        }
    }

    return $working_date;
}
function isWeekend($check_date) {
    return (date("N",  strtotime($check_date)) > 5);
}
function confirm_holiday($somedate="") {
    if ($somedate=="") {
        $somedate = date("Y-m-d");
    }
    $year = date("Y", strtotime($somedate));
    $blnHoliday = false;
    //newyears
    if ($somedate == observed_day($year, 1, 1)) {
        $blnHoliday = true;
    }
    if ($somedate == format_date($year, 1, 1)) {
        $blnHoliday = true;
    }
    if ($somedate == format_date($year, 12, 31)) {
        $blnHoliday = true;
    }
    //Martin Luther King
    if ($somedate == get_holiday($year, 1, 1, 3)) {
        $blnHoliday = true;
    }
    //President's
    if ($somedate == get_holiday($year, 2, 1, 3)) {
        $blnHoliday = true;
    }
    //easter
    if ($somedate == calculate_easter($year)) {
        $blnHoliday = true;
    }
    //Memorial
    if ($somedate == get_holiday($year, 5, 1)) {
        $blnHoliday = true;
    }
    //july4
    if ($somedate == observed_day($year, 7, 4)) {
        $blnHoliday = true;
    }
    //labor
    if ($somedate == get_holiday($year, 9, 1, 1)) {
        $blnHoliday = true;
    }
    //columbus
    if ($somedate == get_holiday($year, 10, 1, 2)) {
        $blnHoliday = true;
    }
    //thanks
    if ($somedate == get_holiday($year, 11, 4, 4)) {
        $blnHoliday = true;
    }
    //xmas
    if ($somedate == format_date($year, 12, 24)) {
        $blnHoliday = true;
    }
    if ($somedate == format_date($year, 12, 25)) {
        $blnHoliday = true;
    }
    return $blnHoliday;
}

This is another solution, it is nearly 25% faster than checking holidays with in_array:

/**
 * Function to calculate the working days between two days, considering holidays.
 * @param string $startDate -- Start date of the range (included), formatted as Y-m-d.
 * @param string $endDate -- End date of the range (included), formatted as Y-m-d.
 * @param array(string) $holidayDates -- OPTIONAL. Array of holidays dates, formatted as Y-m-d. (e.g. array("2016-08-15", "2016-12-25"))
 * @return int -- Number of working days.
 */
function getWorkingDays($startDate, $endDate, $holidayDates=array()){
    $dateRange = new DatePeriod(new DateTime($startDate), new DateInterval('P1D'), (new DateTime($endDate))->modify("+1day"));
    foreach ($dateRange as $dr) { if($dr->format("N")<6){$workingDays[]=$dr->format("Y-m-d");} }
    return count(array_diff($workingDays, $holidayDates));
}

For holidays, make an array of days in some format that date() can produce. Example:

// I know, these aren't holidays
$holidays = array(
    'Jan 2',
    'Feb 3',
    'Mar 5',
    'Apr 7',
    // ...
);

Then use the in_array() and date() functions to check if the timestamp represents a holiday:

$day_of_year = date('M j', $timestamp);
$is_holiday = in_array($day_of_year, $holidays);

https://github.com/Arbitr108/useful_php Here is a class which can estimate the working days into calendar. So after estimation simply add calendar period to the date you need

There are some args for the date() function that should help. If you check date("w") it will give you a number for the day of the week, from 0 for Sunday through 6 for Saturday. So.. maybe something like..

$busDays = 3;
$day = date("w");
if( $day > 2 && $day <= 5 ) { /* if between Wed and Fri */
  $day += 2; /* add 2 more days for weekend */
}
$day += $busDays;

This is just a rough example of one possibility..

For holidays, make an array of days in some format that date() can produce. Example:

// I know, these aren't holidays
$holidays = array(
    'Jan 2',
    'Feb 3',
    'Mar 5',
    'Apr 7',
    // ...
);

Then use the in_array() and date() functions to check if the timestamp represents a holiday:

$day_of_year = date('M j', $timestamp);
$is_holiday = in_array($day_of_year, $holidays);

date_default_timezone_set('America/New_York');


/** Given a number days out, what day is that when counting by 'business' days
  * get the next business day. by default it looks for next business day
  * ie calling  $date = get_next_busines_day(); on monday will return tuesday
  *             $date = get_next_busines_day(2); on monday will return wednesday
  *             $date = get_next_busines_day(2); on friday will return tuesday
  *
  * @param $number_of_business_days (integer)       how many business days out do you want
  * @param $start_date (string)                     strtotime parseable time value
  * @param $ignore_holidays (boolean)               true/false to ignore holidays
  * @param $return_format (string)                  as specified in php.net/date
 */
function get_next_business_day($number_of_business_days=1,$start_date='today',$ignore_holidays=false,$return_format='m/d/y') {

    // get the start date as a string to time
    $result = strtotime($start_date);

    // now keep adding to today's date until number of business days is 0 and we land on a business day
    while ($number_of_business_days > 0) {
        // add one day to the start date
        $result = strtotime(date('Y-m-d',$result) . " + 1 day");

        // this day counts if it's a weekend and not a holiday, or if we choose to ignore holidays
        if (is_weekday(date('Y-m-d',$result)) && (!(is_holiday(date('Y-m-d',$result))) || $ignore_holidays) ) 
            $number_of_business_days--;

    }

    // when my $number of business days is exausted I have my final date

    return(date($return_format,$result));
}

    function is_weekend($date) {
    // return if this is a weekend date or not.
    return (date('N', strtotime($date)) >= 6);
}

function is_weekday($date) {
    // return if this is a weekend date or not.
    return (date('N', strtotime($date)) < 6);
}

function is_holiday($date) {
    // return if this is a holiday or not.

    // what are my holidays for this year
    $holidays = array("New Year's Day 2011" => "12/31/10",
                        "Good Friday" => "04/06/12",
                        "Memorial Day" => "05/28/12",
                        "Independence Day" => "07/04/12",
                        "Floating Holiday" => "12/31/12",
                        "Labor Day" => "09/03/12",
                        "Thanksgiving Day" => "11/22/12",
                        "Day After Thanksgiving Day" => "11/23/12",
                        "Christmas Eve" => "12/24/12",
                        "Christmas Day" => "12/25/12",
                        "New Year's Day 2012" => "01/02/12",
                        "New Year's Day 2013" => "01/01/13"
                        );

    return(in_array(date('m/d/y', strtotime($date)),$holidays));
}


print get_next_business_day(1) . "\n";

$startDate = new DateTime( '2013-04-01' );    //intialize start date
$endDate = new DateTime( '2013-04-30' );    //initialize end date
$holiday = array('2013-04-11','2013-04-25');  //this is assumed list of holiday
$interval = new DateInterval('P1D');    // set the interval as 1 day
$daterange = new DatePeriod($startDate, $interval ,$endDate);
foreach($daterange as $date){
if($date->format("N") <6 AND !in_array($date->format("Y-m-d"),$holiday))
$result[] = $date->format("Y-m-d");
}
echo "<pre>";print_r($result);

PHPClasses have a nice class for this named PHP Working Days. You can check this class.

I just created this function, which seems to work very well:

function getBusinessDays($date1, $date2){

    if(!is_numeric($date1)){
        $date1 = strtotime($date1);
    }

    if(!is_numeric($date2)){
        $date2 = strtotime($date2);
    }

    if($date2 < $date1){
        $temp_date = $date1;
        $date1 = $date2;
        $date2 = $temp_date;
        unset($temp_date);
    }

    $diff = $date2 - $date1;

    $days_diff = intval($diff / (3600 * 24));
    $current_day_of_week = intval(date("N", $date1));
    $business_days = 0;

    for($i = 1; $i <= $days_diff; $i++){
        if(!in_array($current_day_of_week, array("Sunday" => 1, "Saturday" => 7))){
            $business_days++;
        }

        $current_day_of_week++;
        if($current_day_of_week > 7){
            $current_day_of_week = 1;
        }
    }

    return $business_days;
}

echo "Business days: " . getBusinessDays("8/15/2014", "8/8/2014");

Get the number of working days without holidays between two dates :

Use example:

echo number_of_working_days('2013-12-23', '2013-12-29');

Output:

3

Function:

function number_of_working_days($from, $to) {
    $workingDays = [1, 2, 3, 4, 5]; # date format = N (1 = Monday, ...)
    $holidayDays = ['*-12-25', '*-01-01', '2013-12-23']; # variable and fixed holidays

    $from = new DateTime($from);
    $to = new DateTime($to);
    $to->modify('+1 day');
    $interval = new DateInterval('P1D');
    $periods = new DatePeriod($from, $interval, $to);

    $days = 0;
    foreach ($periods as $period) {
        if (!in_array($period->format('N'), $workingDays)) continue;
        if (in_array($period->format('Y-m-d'), $holidayDays)) continue;
        if (in_array($period->format('*-m-d'), $holidayDays)) continue;
        $days++;
    }
    return $days;
}

An enhancement to the function offered by James Pasta above, to include all Federal Holidays, and to correct 4th July (was calculated as 4th June above!), and to also include the holiday name as the array key...

/**
* National American Holidays
* @param string $year
* @return array
*/
public static function getNationalAmericanHolidays($year) {

//  January 1 - New Year's Day (Observed)
//  Third Monday in January - Birthday of Martin Luther King, Jr.
//  Third Monday in February - Washington’s Birthday / President's Day
//  Last Monday in May - Memorial Day
//  July 4 - Independence Day
//  First Monday in September - Labor Day
//  Second Monday in October - Columbus Day
//  November 11 - Veterans’ Day (Observed)
//  Fourth Thursday in November Thanksgiving Day
//  December 25 - Christmas Day
$bankHolidays = array(
    ['New Years Day'] => $year . "-01-01",
    ['Martin Luther King Jr Birthday'] => "". date("Y-m-d",strtotime("third Monday of January " . $year) ),
    ['Washingtons Birthday'] => "". date("Y-m-d",strtotime("third Monday of February " . $year) ),
    ['Memorial Day'] => "". date("Y-m-d",strtotime("last Monday of May " . $year) ),
    ['Independance Day'] => $year . "-07-04",
    ['Labor Day'] => "". date("Y-m-d",strtotime("first Monday of September " . $year) ),
    ['Columbus Day'] => "". date("Y-m-d",strtotime("second Monday of October " . $year) ),
    ['Veterans Day'] => $year . "-11-11",
    ['Thanksgiving Day'] => "". date("Y-m-d",strtotime("fourth Thursday of November " . $year) ),
    ['Christmas Day'] => $year . "-12-25"
);

return $bankHolidays;

}

PHPClasses have a nice class for this named PHP Working Days. You can check this class.

Here is a recursive solution. It can easily be modified to only keep track of and return the latest date.

//  Returns a $numBusDays-sized array of all business dates, 
//  starting from and including $currentDate. 
//  Any date in $holidays will be skipped over.

function getWorkingDays($currentDate, $numBusDays, $holidays = array(), 
  $resultDates = array())
{
  //  exit when we have collected the required number of business days
  if ($numBusDays === 0) {
    return $resultDates;
  }

  //  add current date to return array, if not a weekend or holiday
  $date = date("w", strtotime($currentDate));
  if ( $date != 0  &&  $date != 6  &&  !in_array($currentDate, $holidays) ) {
    $resultDates[] = $currentDate;
    $numBusDays -= 1;
  }

  //  set up the next date to test
  $currentDate = new DateTime("$currentDate + 1 day");
  $currentDate = $currentDate->format('Y-m-d');

  return getWorkingDays($currentDate, $numBusDays, $holidays, $resultDates);
}

//  test
$days = getWorkingDays('2008-12-05', 4);
print_r($days);

<?php
// $today is the UNIX timestamp for today's date
$today = time();
echo "<strong>Today is (ORDER DATE): " . '<font color="red">' . date('l, F j, Y', $today) . "</font></strong><br/><br/>";

//The numerical representation for day of week (Ex. 01 for Monday .... 07 for Sunday
$today_numerical = date("N",$today);

//leadtime_days holds the numeric value for the number of business days 
$leadtime_days = $_POST["leadtime"];

//leadtime is the adjusted date for shipdate
$shipdate = time();

while ($leadtime_days > 0) 
{
 if ($today_numerical != 5 && $today_numerical != 6)
 {
  $shipdate = $shipdate + (60*60*24);
  $today_numerical = date("N",$shipdate);
  $leadtime_days --;
 }
 else
  $shipdate = $shipdate + (60*60*24);
  $today_numerical = date("N",$shipdate);
}

echo '<strong>Estimated Ship date: ' . '<font color="green">' . date('l, F j, Y', $shipdate) . "</font></strong>";
?>

Below is the working code to calculate working business days from a given date.

<?php
$holiday_date_array = array("2016-01-26", "2016-03-07", "2016-03-24", "2016-03-25", "2016-04-15", "2016-08-15", "2016-09-12", "2016-10-11", "2016-10-31");
$date_required = "2016-03-01";

function increase_date($date_required, $holiday_date_array=array(), $days = 15){
    if(!empty($date_required)){
        $counter_1=0;
        $incremented_date = '';
        for($i=1; $i <= $days; $i++){
            $date = strtotime("+$i day", strtotime($date_required));
            $day_name = date("D", $date);
            $incremented_date = date("Y-m-d", $date);
            if($day_name=='Sat'||$day_name=='Sun'|| in_array($incremented_date ,$holiday_date_array)==true){
                $counter_1+=1;
            }
        }
        if($counter_1 > 0){
            return increase_date($incremented_date, $holiday_date_array, $counter_1);
        }else{
            return $incremented_date;
        }
    }else{
        return 'invalid';
    }
}

echo increase_date($date_required, $holiday_date_array, 15);
?>

//output after adding 15 business working days in 2016-03-01 will be "2016-03-23"

For holidays, make an array of days in some format that date() can produce. Example:

// I know, these aren't holidays
$holidays = array(
    'Jan 2',
    'Feb 3',
    'Mar 5',
    'Apr 7',
    // ...
);

Then use the in_array() and date() functions to check if the timestamp represents a holiday:

$day_of_year = date('M j', $timestamp);
$is_holiday = in_array($day_of_year, $holidays);

calculate workdays between two dates including holidays and custom workweek

The answer is not that trivial - thus my suggestion would be to use a class where you can configure more than relying on simplistic function (or assuming a fixed locale and culture). To get the date after a certain number of workdays you'll:

1. need to specify what weekdays you'll be working (default to MON-FRI) - the class allows you to enable or disable each weekday individually.
2. need to know that you need to consider public holidays (country and state) to be accurate
   • e.g. https://github.com/khatfield/php-HolidayLibrary/blob/master/Holidays.class.php
   • or hardcode the data: e.g. from http://www.feiertagskalender.ch/?hl=en
   • or pay for data-API http://www.timeanddate.com/services/api/holiday-api.html

Functional Approach

/**
 * @param days, int
 * @param $format, string: dateformat (if format defined OTHERWISE int: timestamp) 
 * @param start, int: timestamp (mktime) default: time() //now
 * @param $wk, bit[]: flags for each workday (0=SUN, 6=SAT) 1=workday, 0=day off
 * @param $holiday, string[]: list of dates, YYYY-MM-DD, MM-DD 
 */
function working_days($days, $format='', $start=null, $week=[0,1,1,1,1,1,0], $holiday=[])
{
    if(is_null($start)) $start = time();
    if($days <= 0) return $start;
    if(count($week) != 7) trigger_error('workweek must contain bit-flags for 7 days');
    if(array_sum($week) == 0) trigger_error('workweek must contain at least one workday');
    $wd = date('w', $start);//0=sun, 6=sat
    $time = $start;
    while($days)
    {
        if(
        $week[$wd]
        && !in_array(date('Y-m-d', $time), $holiday)
        && !in_array(date('m-d', $time), $holiday)
        ) --$days; //decrement on workdays
        $wd = date('w', $time += 86400); //add one day in seconds
    }
    $time -= 86400;//include today
    return $format ? date($format, $time): $time;
}

//simple usage
$ten_days = working_days(10, 'D F d Y');
echo '<br>ten workingdays (MON-FRI) disregarding holidays: ',$ten_days;

//work on saturdays and add new years day as holiday
$ten_days = working_days(10, 'D F d Y', null, [0,1,1,1,1,1,1], ['01-01']);
echo '<br>ten workingdays (MON-SAT) disregarding holidays: ',$ten_days;

You can try this function which is more simple.

function getWorkingDays($startDate, $endDate)
{
    $begin = strtotime($startDate);
    $end   = strtotime($endDate);
    if ($begin > $end) {

        return 0;
    } else {
        $no_days  = 0;
        while ($begin <= $end) {
            $what_day = date("N", $begin);
            if (!in_array($what_day, [6,7]) ) // 6 and 7 are weekend
                $no_days++;
            $begin += 86400; // +1 day
        };

        return $no_days;
    }
}

There is a Formula:

number_of_days - math_round_down(10 * (number_of_days / (business_days_in_a_week * days_in_a_week)))

Tada! you calculate the numbers of business day, in a month, in a week, in a whatever you want.

math_round_down () is a hypothetical method, which implements a mathematical function that rounds down.

Although this question has over 35 answers at the time of writing, there is a better solution to this problem.

@flamingLogos provided an answer which is based on Mathematics and doesn't contain any loops. That solution provides a time complexity of T(1). However, the math behind it is pretty complex especially the leap year handling.

@Glavic provided a good solution that is minimal and elegant. But it doesn't preform the calculation in a constant time, so it could produce a denial of service (DOS) attack or at least timeout if used with large periods like 10 or 100 of years since it loops on 1 day interval.

So I propose a mathematical approach that have constant time and yet very readable.

The idea is to count how many days to have complete weeks.

<?php
function getWorkingHours($start_date, $end_date) {
    // validate input
    if(!validateDate($start_date) || !validateDate($end_date)) return ['error' => 'Invalid Date'];
    if($end_date < $start_date) return ['error' => 'End date must be greater than or equal Start date'];

    //We save timezone and switch to UTC to prevent issues
    $old_timezone = date_default_timezone_get();
    date_default_timezone_set("UTC");

    $startDate = strtotime($start_date);
    $endDate = strtotime($end_date);

    //The total number of days between the two dates. We compute the no. of seconds and divide it to 60*60*24
    //We add one to include both dates in the interval.
    $days = ($endDate - $startDate) / 86400 + 1;
    $no_full_weeks = ceil($days / 7);
    //we get only missing days count to complete full weeks
    //we take modulo 7 in case it was already full weeks
    $no_of_missing_days = (7 - ($days % 7)) % 7;

    $workingDays = $no_full_weeks * 5;
    //Next we remove the working days we added, this loop will have max of 6 iterations.
    for ($i = 1; $i <= $no_of_missing_days; $i++){
        if(date('N', $endDate + $i * 86400) < 6) $workingDays--;
    }

    $holidays = getHolidays(date('Y', $startDate), date('Y', $endDate));

    //We subtract the holidays
    foreach($holidays as $holiday){
        $time_stamp=strtotime($holiday);
        //If the holiday doesn't fall in weekend
        if ($startDate <= $time_stamp && $time_stamp <= $endDate && date("N",$time_stamp) != 6 && date("N",$time_stamp) != 7)
            $workingDays--;
    }

    date_default_timezone_set($old_timezone);
    return ['days' => $workingDays];

}

The input to the function are in the format of Y-m-d in php or yyyy-mm-dd in general date format.

The get holiday function will return an array of holiday dates starting from start year and until end year.

<?php 
function AddWorkDays(){
$i = 0;
$d = 5; // Number of days to add

    while($i <= $d) {
    $i++;
        if(date('N', mktime(0, 0, 0, date(m), date(d)+$i, date(Y))) < 5) {
            $d++;
        }
    }
    return date(Y).','.date(m).','.(date(d)+$d);
}
?>

I had this same need i started with bobbin's first example and ended up with this

  function add_business_days($startdate,$buisnessdays,$holidays=array(),$dateformat){
    $enddate = strtotime($startdate);
    $day = date('N',$enddate);
    while($buisnessdays > 1){
        $enddate = strtotime(date('Y-m-d',$enddate).' +1 day');
        $day = date('N',$enddate);
        if($day < 6 && !in_array($enddate,$holidays))$buisnessdays--;
    }
    return date($dateformat,$enddate);
  }

hth someone

I figured you might want to include a list of UK holidays, so here's that:

<?php

class ProductionDays
{

    private function getHolidays()
    {
        //from https://www.gov.uk/bank-holidays.json
        $holidaysData = '{"england-and-wales":{"division":"england-and-wales","events":[{"title":"New Year’s Day","date":"2015-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2015-04-03","notes":"","bunting":false},{"title":"Easter Monday","date":"2015-04-06","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2015-05-04","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2015-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2015-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2015-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2015-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2016-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2016-03-25","notes":"","bunting":false},{"title":"Easter Monday","date":"2016-03-28","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2016-05-02","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2016-05-30","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2016-08-29","notes":"","bunting":true},{"title":"Boxing Day","date":"2016-12-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2016-12-27","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2017-01-02","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2017-04-14","notes":"","bunting":false},{"title":"Easter Monday","date":"2017-04-17","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2017-05-01","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2017-05-29","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2017-08-28","notes":"","bunting":true},{"title":"Christmas Day","date":"2017-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2017-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2018-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2018-03-30","notes":"","bunting":false},{"title":"Easter Monday","date":"2018-04-02","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2018-05-07","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2018-05-28","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2018-08-27","notes":"","bunting":true},{"title":"Christmas Day","date":"2018-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2018-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2019-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2019-04-19","notes":"","bunting":false},{"title":"Easter Monday","date":"2019-04-22","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2019-05-06","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2019-05-27","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2019-08-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2019-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2019-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2020-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2020-04-10","notes":"","bunting":false},{"title":"Easter Monday","date":"2020-04-13","notes":"","bunting":true},{"title":"Early May bank holiday (VE day)","date":"2020-05-08","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2020-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2020-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2020-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2020-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2021-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2021-04-02","notes":"","bunting":false},{"title":"Easter Monday","date":"2021-04-05","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2021-05-03","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2021-05-31","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2021-08-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2021-12-27","notes":"Substitute day","bunting":true},{"title":"Boxing Day","date":"2021-12-28","notes":"Substitute day","bunting":true}]},"scotland":{"division":"scotland","events":[{"title":"New Year’s Day","date":"2015-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2015-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2015-04-03","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2015-05-04","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2015-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2015-08-03","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2015-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2015-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2015-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2016-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2016-01-04","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2016-03-25","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2016-05-02","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2016-05-30","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2016-08-01","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2016-11-30","notes":"","bunting":true},{"title":"Boxing Day","date":"2016-12-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2016-12-27","notes":"Substitute day","bunting":true},{"title":"2nd January","date":"2017-01-02","notes":"","bunting":true},{"title":"New Year’s Day","date":"2017-01-03","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2017-04-14","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2017-05-01","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2017-05-29","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2017-08-07","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2017-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2017-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2017-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2018-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2018-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2018-03-30","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2018-05-07","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2018-05-28","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2018-08-06","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2018-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2018-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2018-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2019-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2019-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2019-04-19","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2019-05-06","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2019-05-27","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2019-08-05","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2019-12-02","notes":"Substitute day","bunting":true},{"title":"Christmas Day","date":"2019-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2019-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2020-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2020-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2020-04-10","notes":"","bunting":false},{"title":"Early May bank holiday (VE day)","date":"2020-05-08","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2020-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2020-08-03","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2020-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2020-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2020-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2021-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2021-01-04","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2021-04-02","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2021-05-03","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2021-05-31","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2021-08-02","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2021-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2021-12-27","notes":"Substitute day","bunting":true},{"title":"Boxing Day","date":"2021-12-28","notes":"Substitute day","bunting":true}]},"northern-ireland":{"division":"northern-ireland","events":[{"title":"New Year’s Day","date":"2015-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2015-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2015-04-03","notes":"","bunting":false},{"title":"Easter Monday","date":"2015-04-06","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2015-05-04","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2015-05-25","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2015-07-13","notes":"Substitute day","bunting":false},{"title":"Summer bank holiday","date":"2015-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2015-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2015-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2016-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2016-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2016-03-25","notes":"","bunting":false},{"title":"Easter Monday","date":"2016-03-28","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2016-05-02","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2016-05-30","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2016-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2016-08-29","notes":"","bunting":true},{"title":"Boxing Day","date":"2016-12-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2016-12-27","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2017-01-02","notes":"Substitute day","bunting":true},{"title":"St Patrick’s Day","date":"2017-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2017-04-14","notes":"","bunting":false},{"title":"Easter Monday","date":"2017-04-17","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2017-05-01","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2017-05-29","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2017-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2017-08-28","notes":"","bunting":true},{"title":"Christmas Day","date":"2017-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2017-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2018-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2018-03-19","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2018-03-30","notes":"","bunting":false},{"title":"Easter Monday","date":"2018-04-02","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2018-05-07","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2018-05-28","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2018-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2018-08-27","notes":"","bunting":true},{"title":"Christmas Day","date":"2018-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2018-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2019-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2019-03-18","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2019-04-19","notes":"","bunting":false},{"title":"Easter Monday","date":"2019-04-22","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2019-05-06","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2019-05-27","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2019-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2019-08-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2019-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2019-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2020-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2020-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2020-04-10","notes":"","bunting":false},{"title":"Easter Monday","date":"2020-04-13","notes":"","bunting":true},{"title":"Early May bank holiday (VE day)","date":"2020-05-08","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2020-05-25","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2020-07-13","notes":"Substitute day","bunting":false},{"title":"Summer bank holiday","date":"2020-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2020-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2020-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2021-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2021-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2021-04-02","notes":"","bunting":false},{"title":"Easter Monday","date":"2021-04-05","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2021-05-03","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2021-05-31","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2021-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2021-08-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2021-12-27","notes":"Substitute day","bunting":true},{"title":"Boxing Day","date":"2021-12-28","notes":"Substitute day","bunting":true}]}}';

        $holidaysArray = json_decode($holidaysData, true);
        $holidays = [];
        foreach ($holidaysArray["england-and-wales"]['events'] as $event) {
            $holidays[] = $event['date'];
        }
        return $holidays;
    }

    public function getWorkingDays($dateFrom, $dateTo)
    {
        $holidays = $this->getHolidays();
        $startDate = new DateTime($dateFrom);
        $endDate = new DateTime($dateTo);
        $interval = new DateInterval('P1D');
        $dateRange = new DatePeriod($startDate, $interval, $endDate);
        $results = [];
        foreach ($dateRange as $date) {
            if ($date->format('N') < 6 && !in_array($date->format('Y-m-d'), $holidays)) {
                $results[] = $date->format("Y-m-d");
            }
        }
        return $results;
    }

}

$dateFrom = '01-01-2020';
$dateTo = '31-01-2020';

$productionDays = new ProductionDays();
$getWorkingDays = $productionDays->getWorkingDays($dateFrom, $dateTo);

echo json_encode($getWorkingDays);

https://github.com/Arbitr108/useful_php Here is a class which can estimate the working days into calendar. So after estimation simply add calendar period to the date you need

Here is a recursive solution. It can easily be modified to only keep track of and return the latest date.

//  Returns a $numBusDays-sized array of all business dates, 
//  starting from and including $currentDate. 
//  Any date in $holidays will be skipped over.

function getWorkingDays($currentDate, $numBusDays, $holidays = array(), 
  $resultDates = array())
{
  //  exit when we have collected the required number of business days
  if ($numBusDays === 0) {
    return $resultDates;
  }

  //  add current date to return array, if not a weekend or holiday
  $date = date("w", strtotime($currentDate));
  if ( $date != 0  &&  $date != 6  &&  !in_array($currentDate, $holidays) ) {
    $resultDates[] = $currentDate;
    $numBusDays -= 1;
  }

  //  set up the next date to test
  $currentDate = new DateTime("$currentDate + 1 day");
  $currentDate = $currentDate->format('Y-m-d');

  return getWorkingDays($currentDate, $numBusDays, $holidays, $resultDates);
}

//  test
$days = getWorkingDays('2008-12-05', 4);
print_r($days);

Brute attempt to detect working time - Monday to Friday 8am-4pm:

if (date('N')<6 && date('G')>8 && date('G')<16) {
   // we have a working time (or check for holidays)
}

I figured you might want to include a list of UK holidays, so here's that:

<?php

class ProductionDays
{

    private function getHolidays()
    {
        //from https://www.gov.uk/bank-holidays.json
        $holidaysData = '{"england-and-wales":{"division":"england-and-wales","events":[{"title":"New Year’s Day","date":"2015-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2015-04-03","notes":"","bunting":false},{"title":"Easter Monday","date":"2015-04-06","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2015-05-04","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2015-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2015-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2015-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2015-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2016-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2016-03-25","notes":"","bunting":false},{"title":"Easter Monday","date":"2016-03-28","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2016-05-02","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2016-05-30","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2016-08-29","notes":"","bunting":true},{"title":"Boxing Day","date":"2016-12-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2016-12-27","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2017-01-02","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2017-04-14","notes":"","bunting":false},{"title":"Easter Monday","date":"2017-04-17","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2017-05-01","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2017-05-29","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2017-08-28","notes":"","bunting":true},{"title":"Christmas Day","date":"2017-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2017-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2018-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2018-03-30","notes":"","bunting":false},{"title":"Easter Monday","date":"2018-04-02","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2018-05-07","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2018-05-28","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2018-08-27","notes":"","bunting":true},{"title":"Christmas Day","date":"2018-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2018-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2019-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2019-04-19","notes":"","bunting":false},{"title":"Easter Monday","date":"2019-04-22","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2019-05-06","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2019-05-27","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2019-08-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2019-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2019-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2020-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2020-04-10","notes":"","bunting":false},{"title":"Easter Monday","date":"2020-04-13","notes":"","bunting":true},{"title":"Early May bank holiday (VE day)","date":"2020-05-08","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2020-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2020-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2020-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2020-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2021-01-01","notes":"","bunting":true},{"title":"Good Friday","date":"2021-04-02","notes":"","bunting":false},{"title":"Easter Monday","date":"2021-04-05","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2021-05-03","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2021-05-31","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2021-08-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2021-12-27","notes":"Substitute day","bunting":true},{"title":"Boxing Day","date":"2021-12-28","notes":"Substitute day","bunting":true}]},"scotland":{"division":"scotland","events":[{"title":"New Year’s Day","date":"2015-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2015-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2015-04-03","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2015-05-04","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2015-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2015-08-03","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2015-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2015-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2015-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2016-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2016-01-04","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2016-03-25","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2016-05-02","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2016-05-30","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2016-08-01","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2016-11-30","notes":"","bunting":true},{"title":"Boxing Day","date":"2016-12-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2016-12-27","notes":"Substitute day","bunting":true},{"title":"2nd January","date":"2017-01-02","notes":"","bunting":true},{"title":"New Year’s Day","date":"2017-01-03","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2017-04-14","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2017-05-01","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2017-05-29","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2017-08-07","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2017-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2017-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2017-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2018-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2018-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2018-03-30","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2018-05-07","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2018-05-28","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2018-08-06","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2018-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2018-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2018-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2019-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2019-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2019-04-19","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2019-05-06","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2019-05-27","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2019-08-05","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2019-12-02","notes":"Substitute day","bunting":true},{"title":"Christmas Day","date":"2019-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2019-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2020-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2020-01-02","notes":"","bunting":true},{"title":"Good Friday","date":"2020-04-10","notes":"","bunting":false},{"title":"Early May bank holiday (VE day)","date":"2020-05-08","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2020-05-25","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2020-08-03","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2020-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2020-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2020-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2021-01-01","notes":"","bunting":true},{"title":"2nd January","date":"2021-01-04","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2021-04-02","notes":"","bunting":false},{"title":"Early May bank holiday","date":"2021-05-03","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2021-05-31","notes":"","bunting":true},{"title":"Summer bank holiday","date":"2021-08-02","notes":"","bunting":true},{"title":"St Andrew’s Day","date":"2021-11-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2021-12-27","notes":"Substitute day","bunting":true},{"title":"Boxing Day","date":"2021-12-28","notes":"Substitute day","bunting":true}]},"northern-ireland":{"division":"northern-ireland","events":[{"title":"New Year’s Day","date":"2015-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2015-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2015-04-03","notes":"","bunting":false},{"title":"Easter Monday","date":"2015-04-06","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2015-05-04","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2015-05-25","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2015-07-13","notes":"Substitute day","bunting":false},{"title":"Summer bank holiday","date":"2015-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2015-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2015-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2016-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2016-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2016-03-25","notes":"","bunting":false},{"title":"Easter Monday","date":"2016-03-28","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2016-05-02","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2016-05-30","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2016-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2016-08-29","notes":"","bunting":true},{"title":"Boxing Day","date":"2016-12-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2016-12-27","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2017-01-02","notes":"Substitute day","bunting":true},{"title":"St Patrick’s Day","date":"2017-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2017-04-14","notes":"","bunting":false},{"title":"Easter Monday","date":"2017-04-17","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2017-05-01","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2017-05-29","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2017-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2017-08-28","notes":"","bunting":true},{"title":"Christmas Day","date":"2017-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2017-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2018-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2018-03-19","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2018-03-30","notes":"","bunting":false},{"title":"Easter Monday","date":"2018-04-02","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2018-05-07","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2018-05-28","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2018-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2018-08-27","notes":"","bunting":true},{"title":"Christmas Day","date":"2018-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2018-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2019-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2019-03-18","notes":"Substitute day","bunting":true},{"title":"Good Friday","date":"2019-04-19","notes":"","bunting":false},{"title":"Easter Monday","date":"2019-04-22","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2019-05-06","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2019-05-27","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2019-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2019-08-26","notes":"","bunting":true},{"title":"Christmas Day","date":"2019-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2019-12-26","notes":"","bunting":true},{"title":"New Year’s Day","date":"2020-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2020-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2020-04-10","notes":"","bunting":false},{"title":"Easter Monday","date":"2020-04-13","notes":"","bunting":true},{"title":"Early May bank holiday (VE day)","date":"2020-05-08","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2020-05-25","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2020-07-13","notes":"Substitute day","bunting":false},{"title":"Summer bank holiday","date":"2020-08-31","notes":"","bunting":true},{"title":"Christmas Day","date":"2020-12-25","notes":"","bunting":true},{"title":"Boxing Day","date":"2020-12-28","notes":"Substitute day","bunting":true},{"title":"New Year’s Day","date":"2021-01-01","notes":"","bunting":true},{"title":"St Patrick’s Day","date":"2021-03-17","notes":"","bunting":true},{"title":"Good Friday","date":"2021-04-02","notes":"","bunting":false},{"title":"Easter Monday","date":"2021-04-05","notes":"","bunting":true},{"title":"Early May bank holiday","date":"2021-05-03","notes":"","bunting":true},{"title":"Spring bank holiday","date":"2021-05-31","notes":"","bunting":true},{"title":"Battle of the Boyne (Orangemen’s Day)","date":"2021-07-12","notes":"","bunting":false},{"title":"Summer bank holiday","date":"2021-08-30","notes":"","bunting":true},{"title":"Christmas Day","date":"2021-12-27","notes":"Substitute day","bunting":true},{"title":"Boxing Day","date":"2021-12-28","notes":"Substitute day","bunting":true}]}}';

        $holidaysArray = json_decode($holidaysData, true);
        $holidays = [];
        foreach ($holidaysArray["england-and-wales"]['events'] as $event) {
            $holidays[] = $event['date'];
        }
        return $holidays;
    }

    public function getWorkingDays($dateFrom, $dateTo)
    {
        $holidays = $this->getHolidays();
        $startDate = new DateTime($dateFrom);
        $endDate = new DateTime($dateTo);
        $interval = new DateInterval('P1D');
        $dateRange = new DatePeriod($startDate, $interval, $endDate);
        $results = [];
        foreach ($dateRange as $date) {
            if ($date->format('N') < 6 && !in_array($date->format('Y-m-d'), $holidays)) {
                $results[] = $date->format("Y-m-d");
            }
        }
        return $results;
    }

}

$dateFrom = '01-01-2020';
$dateTo = '31-01-2020';

$productionDays = new ProductionDays();
$getWorkingDays = $productionDays->getWorkingDays($dateFrom, $dateTo);

echo json_encode($getWorkingDays);

Personally, I think this is a cleaner and more concise solution:

function onlyWorkDays( $d ) {
    $holidays = array('2013-12-25','2013-12-31','2014-01-01','2014-01-20','2014-02-17','2014-05-26','2014-07-04','2014-09-01','2014-10-13','2014-11-11','2014-11-27','2014-12-25','2014-12-31');
    while (in_array($d->format("Y-m-d"), $holidays)) { // HOLIDAYS
        $d->sub(new DateInterval("P1D"));
    }
    if ($d->format("w") == 6) { // SATURDAY
        $d->sub(new DateInterval("P1D"));
    }
    if ($d->format("w") == 0) { // SUNDAY
        $d->sub(new DateInterval("P2D"));
    }
    return $d;
}

Just send the proposed new date to this function.

My version based on the work by @mcgrailm... tweaked because the report needed to be reviewed within 3 business days, and if submitted on a weekend, the counting would start on the following Monday:

function business_days_add($start_date, $business_days, $holidays = array()) {
    $current_date = strtotime($start_date);
    $business_days = intval($business_days); // Decrement does not work on strings
    while ($business_days > 0) {
        if (date('N', $current_date) < 6 && !in_array(date('Y-m-d', $current_date), $holidays)) {
            $business_days--;
        }
        if ($business_days > 0) {
            $current_date = strtotime('+1 day', $current_date);
        }
    }
    return $current_date;
}

And working out the difference of two dates in terms of business days:

function business_days_diff($start_date, $end_date, $holidays = array()) {
    $business_days = 0;
    $current_date = strtotime($start_date);
    $end_date = strtotime($end_date);
    while ($current_date <= $end_date) {
        if (date('N', $current_date) < 6 && !in_array(date('Y-m-d', $current_date), $holidays)) {
            $business_days++;
        }
        if ($current_date <= $end_date) {
            $current_date = strtotime('+1 day', $current_date);
        }
    }
    return $business_days;
}

As a note, everyone who is using 86400, or 24*60*60, please don't... your forgetting time changes from winter/summer time, where a day it not exactly 24 hours. While it's a little slower the strtotime('+1 day', $timestamp), it much more reliable.

You can try this function which is more simple.

function getWorkingDays($startDate, $endDate)
{
    $begin = strtotime($startDate);
    $end   = strtotime($endDate);
    if ($begin > $end) {

        return 0;
    } else {
        $no_days  = 0;
        while ($begin <= $end) {
            $what_day = date("N", $begin);
            if (!in_array($what_day, [6,7]) ) // 6 and 7 are weekend
                $no_days++;
            $begin += 86400; // +1 day
        };

        return $no_days;
    }
}

Thanks to Bobbin, mcgrailm, Tony, James Pasta and a few others who posted here. I had written my own function to add business days to a date, but modified it with some code I found here. This will handle the start date being on a weekend/holiday. This will also handle business hours. I added some comments and break up the code to make it easier to read.

<?php
function count_business_days($date, $days, $holidays) {
    $date = strtotime($date);

    for ($i = 1; $i <= intval($days); $i++) { //Loops each day count

        //First, find the next available weekday because this might be a weekend/holiday
        while (date('N', $date) >= 6 || in_array(date('Y-m-d', $date), $holidays)){
            $date = strtotime(date('Y-m-d',$date).' +1 day');
        }

        //Now that we know we have a business day, add 1 day to it
        $date = strtotime(date('Y-m-d',$date).' +1 day');

        //If this day that was previously added falls on a weekend/holiday, then find the next business day
        while (date('N', $date) >= 6 || in_array(date('Y-m-d', $date), $holidays)){
            $date = strtotime(date('Y-m-d',$date).' +1 day');
        }
    }
    return date('Y-m-d', $date);
}

//Also add in the code from Tony and James Pasta to handle holidays...

function getNationalAmericanHolidays($year) {
$bankHolidays = array(
    'New Years Day' => $year . "-01-01",
    'Martin Luther King Jr Birthday' => "". date("Y-m-d",strtotime("third Monday of January " . $year) ),
    'Washingtons Birthday' => "". date("Y-m-d",strtotime("third Monday of February " . $year) ),
    'Memorial Day' => "". date("Y-m-d",strtotime("last Monday of May " . $year) ),
    'Independance Day' => $year . "-07-04",
    'Labor Day' => "". date("Y-m-d",strtotime("first Monday of September " . $year) ),
    'Columbus Day' => "". date("Y-m-d",strtotime("second Monday of October " . $year) ),
    'Veterans Day' => $year . "-11-11",
    'Thanksgiving Day' => "". date("Y-m-d",strtotime("fourth Thursday of November " . $year) ),
    'Christmas Day' => $year . "-12-25"
);
return $bankHolidays;

}

//Now to call it... since we're working with business days, we should
//also be working with business hours so check if it's after 5 PM
//and go to the next day if necessary.

//Go to next day if after 5 pm (5 pm = 17)
if (date(G) >= 17) {
    $start_date = date("Y-m-d", strtotime("+ 1 day")); //Tomorrow
} else {
    $start_date = date("Y-m-d"); //Today
}

//Get the holidays for the current year and also for the next year
$this_year = getNationalAmericanHolidays(date('Y'));
$next_year = getNationalAmericanHolidays(date('Y', strtotime("+12 months")));
$holidays = array_merge($this_year, $next_year);

//The number of days to count
$days_count = 10;

echo count_business_days($start_date, $days_count, $holidays);

?>

An enhancement to the function offered by James Pasta above, to include all Federal Holidays, and to correct 4th July (was calculated as 4th June above!), and to also include the holiday name as the array key...

/**
* National American Holidays
* @param string $year
* @return array
*/
public static function getNationalAmericanHolidays($year) {

//  January 1 - New Year's Day (Observed)
//  Third Monday in January - Birthday of Martin Luther King, Jr.
//  Third Monday in February - Washington’s Birthday / President's Day
//  Last Monday in May - Memorial Day
//  July 4 - Independence Day
//  First Monday in September - Labor Day
//  Second Monday in October - Columbus Day
//  November 11 - Veterans’ Day (Observed)
//  Fourth Thursday in November Thanksgiving Day
//  December 25 - Christmas Day
$bankHolidays = array(
    ['New Years Day'] => $year . "-01-01",
    ['Martin Luther King Jr Birthday'] => "". date("Y-m-d",strtotime("third Monday of January " . $year) ),
    ['Washingtons Birthday'] => "". date("Y-m-d",strtotime("third Monday of February " . $year) ),
    ['Memorial Day'] => "". date("Y-m-d",strtotime("last Monday of May " . $year) ),
    ['Independance Day'] => $year . "-07-04",
    ['Labor Day'] => "". date("Y-m-d",strtotime("first Monday of September " . $year) ),
    ['Columbus Day'] => "". date("Y-m-d",strtotime("second Monday of October " . $year) ),
    ['Veterans Day'] => $year . "-11-11",
    ['Thanksgiving Day'] => "". date("Y-m-d",strtotime("fourth Thursday of November " . $year) ),
    ['Christmas Day'] => $year . "-12-25"
);

return $bankHolidays;

}

Just finished writing an API that can be used to manipulate business days (none of these solutions quite worked for my situation :-); linking to it here in case anyone else finds it useful.

~ Nate

PHP Class to Calculate Business Days

A function to add or subtract business days from a given date, this doesn't account for holidays.

function dateFromBusinessDays($days, $dateTime=null) {
  $dateTime = is_null($dateTime) ? time() : $dateTime;
  $_day = 0;
  $_direction = $days == 0 ? 0 : intval($days/abs($days));
  $_day_value = (60 * 60 * 24);

  while($_day !== $days) {
    $dateTime += $_direction * $_day_value;

    $_day_w = date("w", $dateTime);
    if ($_day_w > 0 && $_day_w < 6) {
      $_day += $_direction * 1; 
    }
  }

  return $dateTime;
}

use like so...

echo date("m/d/Y", dateFromBusinessDays(-7));
echo date("m/d/Y", dateFromBusinessDays(3, time() + 3*60*60*24));

The add_business_days has a small bug. Try the following with the existing function and the output will be a Saturday.

Startdate = Friday Business days to add = 1 Holidays array = Add date for the following Monday.

I have fixed that in my function below.

function add_business_days($startdate, $buisnessdays, $holidays = array(), $dateformat = 'Y-m-d'){
$i= 1;
$dayx= strtotime($startdate);
$buisnessdays= ceil($buisnessdays);

while($i < $buisnessdays)
{
    $day= date('N',$dayx);

    $date= date('Y-m-d',$dayx);
    if($day < 6 && !in_array($date,$holidays))
        $i++;

    $dayx= strtotime($date.' +1 day');
}

## If the calculated day falls on a weekend or is a holiday, then add days to the next business day
$day= date('N',$dayx);
$date= date('Y-m-d',$dayx);

while($day >= 6 || in_array($date,$holidays))
{
    $dayx= strtotime($date.' +1 day');
    $day= date('N',$dayx);
    $date= date('Y-m-d',$dayx);
}

return date($dateformat, $dayx);}

Personally, I think this is a cleaner and more concise solution:

function onlyWorkDays( $d ) {
    $holidays = array('2013-12-25','2013-12-31','2014-01-01','2014-01-20','2014-02-17','2014-05-26','2014-07-04','2014-09-01','2014-10-13','2014-11-11','2014-11-27','2014-12-25','2014-12-31');
    while (in_array($d->format("Y-m-d"), $holidays)) { // HOLIDAYS
        $d->sub(new DateInterval("P1D"));
    }
    if ($d->format("w") == 6) { // SATURDAY
        $d->sub(new DateInterval("P1D"));
    }
    if ($d->format("w") == 0) { // SUNDAY
        $d->sub(new DateInterval("P2D"));
    }
    return $d;
}

Just send the proposed new date to this function.

For holidays, make an array of days in some format that date() can produce. Example:

// I know, these aren't holidays
$holidays = array(
    'Jan 2',
    'Feb 3',
    'Mar 5',
    'Apr 7',
    // ...
);

Then use the in_array() and date() functions to check if the timestamp represents a holiday:

$day_of_year = date('M j', $timestamp);
$is_holiday = in_array($day_of_year, $holidays);

There are some args for the date() function that should help. If you check date("w") it will give you a number for the day of the week, from 0 for Sunday through 6 for Saturday. So.. maybe something like..

$busDays = 3;
$day = date("w");
if( $day > 2 && $day <= 5 ) { /* if between Wed and Fri */
  $day += 2; /* add 2 more days for weekend */
}
$day += $busDays;

This is just a rough example of one possibility..

Variant 1:

<?php
/*
 * Does not count current day, the date returned is the last business day
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = time();
    while ($bDays>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6) $bDays--;
    }
    return $timestamp;
}

Variant 2:

<?php
/*
 * Does not count current day, the date returned is a business day 
 * following the last business day
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = time();
    while ($bDays+1>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6) $bDays--;
    }
    return $timestamp;
}

Variant 3:

<?php
/*
 * Does not count current day, the date returned is 
 * a date following the last business day (can be weekend or not. 
 * See above for alternatives)
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = time();
    while ($bDays>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6) $bDays--;
    }
    return $timestamp += 86400;
}

The additional holiday considerations can be made using variations of the above by doing the following. Note! assure all the timestamps are the same time of the day (i.e. midnight).

Make an array of holiday dates (as unixtimestamps) i.e.:

$holidays = array_flip(strtotime('2011-01-01'),strtotime('2011-12-25'));

Modify line :

if (date('N', $timestamp)<6) $bDays--;

to be :

if (date('N', $timestamp)<6 && !isset($holidays[$timestamp])) $bDays--;

Done!

<?php
/*
 * Does not count current day, the date returned is the last business day
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = strtotime(date('Y-m-d',time()));
    $holidays = array_flip(strtotime('2011-01-01'),strtotime('2011-12-25'));
    while ($bDays>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6 && !isset($holidays[$timestamp])) $bDays--;
    }
    return $timestamp;
}

There are some args for the date() function that should help. If you check date("w") it will give you a number for the day of the week, from 0 for Sunday through 6 for Saturday. So.. maybe something like..

$busDays = 3;
$day = date("w");
if( $day > 2 && $day <= 5 ) { /* if between Wed and Fri */
  $day += 2; /* add 2 more days for weekend */
}
$day += $busDays;

This is just a rough example of one possibility..

A function to add or subtract business days from a given date, this doesn't account for holidays.

function dateFromBusinessDays($days, $dateTime=null) {
  $dateTime = is_null($dateTime) ? time() : $dateTime;
  $_day = 0;
  $_direction = $days == 0 ? 0 : intval($days/abs($days));
  $_day_value = (60 * 60 * 24);

  while($_day !== $days) {
    $dateTime += $_direction * $_day_value;

    $_day_w = date("w", $dateTime);
    if ($_day_w > 0 && $_day_w < 6) {
      $_day += $_direction * 1; 
    }
  }

  return $dateTime;
}

use like so...

echo date("m/d/Y", dateFromBusinessDays(-7));
echo date("m/d/Y", dateFromBusinessDays(3, time() + 3*60*60*24));

This code snippet is very easy to calculate business day without week end and holidays:

function getWorkingDays($startDate,$endDate,$offdays,$holidays){
$endDate = strtotime($endDate);
$startDate = strtotime($startDate);
$days = ($endDate - $startDate) / 86400 + 1;
$counter=0;
for ($i = 1; $i <= $days; $i++) {
    $the_first_day_of_week = date("N", $startDate);
    $startDate+=86400;
if (!in_array($the_first_day_of_week, $offdays) && !in_array(date("Y-m-
d",$startDate), $holidays)) {
$counter++;
}

}   
return $counter;
}
//example to use
$holidays=array("2017-07-03","2017-07-20");
$offdays=array(5,6);//weekend days Monday=1 .... Sunday=7
echo getWorkingDays("2017-01-01","2017-12-31",$offdays,$holidays)

<?php 
function AddWorkDays(){
$i = 0;
$d = 5; // Number of days to add

    while($i <= $d) {
    $i++;
        if(date('N', mktime(0, 0, 0, date(m), date(d)+$i, date(Y))) < 5) {
            $d++;
        }
    }
    return date(Y).','.date(m).','.(date(d)+$d);
}
?>

The add_business_days has a small bug. Try the following with the existing function and the output will be a Saturday.

Startdate = Friday Business days to add = 1 Holidays array = Add date for the following Monday.

I have fixed that in my function below.

function add_business_days($startdate, $buisnessdays, $holidays = array(), $dateformat = 'Y-m-d'){
$i= 1;
$dayx= strtotime($startdate);
$buisnessdays= ceil($buisnessdays);

while($i < $buisnessdays)
{
    $day= date('N',$dayx);

    $date= date('Y-m-d',$dayx);
    if($day < 6 && !in_array($date,$holidays))
        $i++;

    $dayx= strtotime($date.' +1 day');
}

## If the calculated day falls on a weekend or is a holiday, then add days to the next business day
$day= date('N',$dayx);
$date= date('Y-m-d',$dayx);

while($day >= 6 || in_array($date,$holidays))
{
    $dayx= strtotime($date.' +1 day');
    $day= date('N',$dayx);
    $date= date('Y-m-d',$dayx);
}

return date($dateformat, $dayx);}

Brute attempt to detect working time - Monday to Friday 8am-4pm:

if (date('N')<6 && date('G')>8 && date('G')<16) {
   // we have a working time (or check for holidays)
}

If you need to get how much time was between two dates you can use https://github.com/maximnara/business-days-counter. It's works simply but only with laravel now $diffInSeconds = $this->datesCounter->getDifferenceInSeconds(Carbon::create(2019, 1, 1), Carbon::now(), DateCounter::COUNTRY_FR);

It doesn't counts public holidays and weekends and you can set working interval, for example from 9 to 18 with launch hour or no.

Or if you need just weekends and you use Carbon you can use built in function:

$date1 = Carbon::create(2019, 1, 1)->endOfDay();
$date2 = $dt->copy()->startOfDay();
$diff = $date1->diffFiltered(CarbonInterval::minute(), function(Carbon $date) {
   return !$date->isWeekend();
}, $date2, true);

But it will foreach every minute in interval, for bit intervals it can take a while.

Below is the working code to calculate working business days from a given date.

<?php
$holiday_date_array = array("2016-01-26", "2016-03-07", "2016-03-24", "2016-03-25", "2016-04-15", "2016-08-15", "2016-09-12", "2016-10-11", "2016-10-31");
$date_required = "2016-03-01";

function increase_date($date_required, $holiday_date_array=array(), $days = 15){
    if(!empty($date_required)){
        $counter_1=0;
        $incremented_date = '';
        for($i=1; $i <= $days; $i++){
            $date = strtotime("+$i day", strtotime($date_required));
            $day_name = date("D", $date);
            $incremented_date = date("Y-m-d", $date);
            if($day_name=='Sat'||$day_name=='Sun'|| in_array($incremented_date ,$holiday_date_array)==true){
                $counter_1+=1;
            }
        }
        if($counter_1 > 0){
            return increase_date($incremented_date, $holiday_date_array, $counter_1);
        }else{
            return $incremented_date;
        }
    }else{
        return 'invalid';
    }
}

echo increase_date($date_required, $holiday_date_array, 15);
?>

//output after adding 15 business working days in 2016-03-01 will be "2016-03-23"

Although this question has over 35 answers at the time of writing, there is a better solution to this problem.

@flamingLogos provided an answer which is based on Mathematics and doesn't contain any loops. That solution provides a time complexity of T(1). However, the math behind it is pretty complex especially the leap year handling.

@Glavic provided a good solution that is minimal and elegant. But it doesn't preform the calculation in a constant time, so it could produce a denial of service (DOS) attack or at least timeout if used with large periods like 10 or 100 of years since it loops on 1 day interval.

So I propose a mathematical approach that have constant time and yet very readable.

The idea is to count how many days to have complete weeks.

<?php
function getWorkingHours($start_date, $end_date) {
    // validate input
    if(!validateDate($start_date) || !validateDate($end_date)) return ['error' => 'Invalid Date'];
    if($end_date < $start_date) return ['error' => 'End date must be greater than or equal Start date'];

    //We save timezone and switch to UTC to prevent issues
    $old_timezone = date_default_timezone_get();
    date_default_timezone_set("UTC");

    $startDate = strtotime($start_date);
    $endDate = strtotime($end_date);

    //The total number of days between the two dates. We compute the no. of seconds and divide it to 60*60*24
    //We add one to include both dates in the interval.
    $days = ($endDate - $startDate) / 86400 + 1;
    $no_full_weeks = ceil($days / 7);
    //we get only missing days count to complete full weeks
    //we take modulo 7 in case it was already full weeks
    $no_of_missing_days = (7 - ($days % 7)) % 7;

    $workingDays = $no_full_weeks * 5;
    //Next we remove the working days we added, this loop will have max of 6 iterations.
    for ($i = 1; $i <= $no_of_missing_days; $i++){
        if(date('N', $endDate + $i * 86400) < 6) $workingDays--;
    }

    $holidays = getHolidays(date('Y', $startDate), date('Y', $endDate));

    //We subtract the holidays
    foreach($holidays as $holiday){
        $time_stamp=strtotime($holiday);
        //If the holiday doesn't fall in weekend
        if ($startDate <= $time_stamp && $time_stamp <= $endDate && date("N",$time_stamp) != 6 && date("N",$time_stamp) != 7)
            $workingDays--;
    }

    date_default_timezone_set($old_timezone);
    return ['days' => $workingDays];

}

The input to the function are in the format of Y-m-d in php or yyyy-mm-dd in general date format.

The get holiday function will return an array of holiday dates starting from start year and until end year.

This is another solution, it is nearly 25% faster than checking holidays with in_array:

/**
 * Function to calculate the working days between two days, considering holidays.
 * @param string $startDate -- Start date of the range (included), formatted as Y-m-d.
 * @param string $endDate -- End date of the range (included), formatted as Y-m-d.
 * @param array(string) $holidayDates -- OPTIONAL. Array of holidays dates, formatted as Y-m-d. (e.g. array("2016-08-15", "2016-12-25"))
 * @return int -- Number of working days.
 */
function getWorkingDays($startDate, $endDate, $holidayDates=array()){
    $dateRange = new DatePeriod(new DateTime($startDate), new DateInterval('P1D'), (new DateTime($endDate))->modify("+1day"));
    foreach ($dateRange as $dr) { if($dr->format("N")<6){$workingDays[]=$dr->format("Y-m-d");} }
    return count(array_diff($workingDays, $holidayDates));
}

I just created this function, which seems to work very well:

function getBusinessDays($date1, $date2){

    if(!is_numeric($date1)){
        $date1 = strtotime($date1);
    }

    if(!is_numeric($date2)){
        $date2 = strtotime($date2);
    }

    if($date2 < $date1){
        $temp_date = $date1;
        $date1 = $date2;
        $date2 = $temp_date;
        unset($temp_date);
    }

    $diff = $date2 - $date1;

    $days_diff = intval($diff / (3600 * 24));
    $current_day_of_week = intval(date("N", $date1));
    $business_days = 0;

    for($i = 1; $i <= $days_diff; $i++){
        if(!in_array($current_day_of_week, array("Sunday" => 1, "Saturday" => 7))){
            $business_days++;
        }

        $current_day_of_week++;
        if($current_day_of_week > 7){
            $current_day_of_week = 1;
        }
    }

    return $business_days;
}

echo "Business days: " . getBusinessDays("8/15/2014", "8/8/2014");

My version based on the work by @mcgrailm... tweaked because the report needed to be reviewed within 3 business days, and if submitted on a weekend, the counting would start on the following Monday:

function business_days_add($start_date, $business_days, $holidays = array()) {
    $current_date = strtotime($start_date);
    $business_days = intval($business_days); // Decrement does not work on strings
    while ($business_days > 0) {
        if (date('N', $current_date) < 6 && !in_array(date('Y-m-d', $current_date), $holidays)) {
            $business_days--;
        }
        if ($business_days > 0) {
            $current_date = strtotime('+1 day', $current_date);
        }
    }
    return $current_date;
}

And working out the difference of two dates in terms of business days:

function business_days_diff($start_date, $end_date, $holidays = array()) {
    $business_days = 0;
    $current_date = strtotime($start_date);
    $end_date = strtotime($end_date);
    while ($current_date <= $end_date) {
        if (date('N', $current_date) < 6 && !in_array(date('Y-m-d', $current_date), $holidays)) {
            $business_days++;
        }
        if ($current_date <= $end_date) {
            $current_date = strtotime('+1 day', $current_date);
        }
    }
    return $business_days;
}

As a note, everyone who is using 86400, or 24*60*60, please don't... your forgetting time changes from winter/summer time, where a day it not exactly 24 hours. While it's a little slower the strtotime('+1 day', $timestamp), it much more reliable.

I just get my function working based on Bobbin and mcgrailm code, adding some things that worked perfect to me.

function add_business_days($startdate,$buisnessdays,$holidays,$dateformat){
    $enddate = strtotime($startdate);
    $day = date('N',$enddate);
    while($buisnessdays > 0){ // compatible with 1 businessday if I'll need it
        $enddate = strtotime(date('Y-m-d',$enddate).' +1 day');
        $day = date('N',$enddate);
        if($day < 6 && !in_array(date('Y-m-d',$enddate),$holidays))$buisnessdays--;
    }
    return date($dateformat,$enddate);
}

// as a parameter in in_array function we should use endate formated to 
// compare correctly with the holidays array.

I know I'm late to the party, but I use this old set of functions by Marcos J. Montes for figuring out holidays and business days. He took the time to add an algorithm from 1876 for Easter and he added all the major US holidays. This can easily be updated for other countries.

//Usage
$days = 30;
$next_working_date = nextWorkingDay($days, $somedate);

//add date function
function DateAdd($interval, $number, $date) {

    $date_time_array = getdate($date);
    //die(print_r($date_time_array));

    $hours = $date_time_array["hours"];
    $minutes = $date_time_array["minutes"];
    $seconds = $date_time_array["seconds"];
    $month = $date_time_array["mon"];
    $day = $date_time_array["mday"];
    $year = $date_time_array["year"];

    switch ($interval) {

        case "yyyy":
            $year+=$number;
            break;
        case "q":
            $year+=($number*3);
            break;
        case "m":
            $month+=$number;
            break;
        case "y":
        case "d":
        case "w":
            $day+=$number;
            break;
        case "ww":
            $day+=($number*7);
            break;
        case "h":
            $hours+=$number;
            break;
        case "n":
            $minutes+=$number;
            break;
        case "s":
            $seconds+=$number; 
            break;            
    }
    //      echo "day:" . $day;
    $timestamp= mktime($hours,$minutes,$seconds,$month,$day,$year);
    return $timestamp;
}

// the following function get_holiday() is based on the work done by
// Marcos J. Montes
function get_holiday($year, $month, $day_of_week, $week="") {
    if ( (($week != "") && (($week > 5) || ($week < 1))) || ($day_of_week > 6) || ($day_of_week < 0) ) {
        // $day_of_week must be between 0 and 6 (Sun=0, ... Sat=6); $week must be between 1 and 5
        return FALSE;
    } else {
        if (!$week || ($week == "")) {
            $lastday = date("t", mktime(0,0,0,$month,1,$year));
            $temp = (date("w",mktime(0,0,0,$month,$lastday,$year)) - $day_of_week) % 7;
        } else {
            $temp = ($day_of_week - date("w",mktime(0,0,0,$month,1,$year))) % 7;
        }

        if ($temp < 0) {
            $temp += 7;
        }

        if (!$week || ($week == "")) {
            $day = $lastday - $temp;
        } else {
            $day = (7 * $week) - 6 + $temp;
        }
        //echo $year.", ".$month.", ".$day . "<br><br>";
        return format_date($year, $month, $day);
    }
}

function observed_day($year, $month, $day) {
    // sat -> fri & sun -> mon, any exceptions?
    //
    // should check $lastday for bumping forward and $firstday for bumping back,
    // although New Year's & Easter look to be the only holidays that potentially
    // move to a different month, and both are accounted for.

    $dow = date("w", mktime(0, 0, 0, $month, $day, $year));

    if ($dow == 0) {
        $dow = $day + 1;
    } elseif ($dow == 6) {
        if (($month == 1) && ($day == 1)) {    // New Year's on a Saturday
            $year--;
            $month = 12;
            $dow = 31;
        } else {
            $dow = $day - 1;
        }
    } else {
        $dow = $day;
    }

    return format_date($year, $month, $dow);
}

function calculate_easter($y) {
    // In the text below, 'intval($var1/$var2)' represents an integer division neglecting
    // the remainder, while % is division keeping only the remainder. So 30/7=4, and 30%7=2
//
    // This algorithm is from Practical Astronomy With Your Calculator, 2nd Edition by Peter
    // Duffett-Smith. It was originally from Butcher's Ecclesiastical Calendar, published in
    // 1876. This algorithm has also been published in the 1922 book General Astronomy by
    // Spencer Jones; in The Journal of the British Astronomical Association (Vol.88, page
    // 91, December 1977); and in Astronomical Algorithms (1991) by Jean Meeus. 

    $a = $y%19;
    $b = intval($y/100);
    $c = $y%100;
    $d = intval($b/4);
    $e = $b%4;
    $f = intval(($b+8)/25);
    $g = intval(($b-$f+1)/3);
    $h = (19*$a+$b-$d-$g+15)%30;
    $i = intval($c/4);
    $k = $c%4;
    $l = (32+2*$e+2*$i-$h-$k)%7;
    $m = intval(($a+11*$h+22*$l)/451);
    $p = ($h+$l-7*$m+114)%31;
    $EasterMonth = intval(($h+$l-7*$m+114)/31);    // [3 = March, 4 = April]
    $EasterDay = $p+1;    // (day in Easter Month)

    return format_date($y, $EasterMonth, $EasterDay);
}


function nextWorkingDay($number_days, $start_date = "") {
    $day_counter = 0;
    $intCounter = 0;    

    if ($start_date=="") {
        $today  = mktime(0, 0, 0, date("m")  , date("d"), date("Y"));
    } else {
        $start_time = strtotime($start_date);
        $today  = mktime(0, 0, 0, date("m", $start_time)  , date("d", $start_time), date("Y", $start_time));
    }

    while($day_counter < $number_days) {
        $working_time = DateAdd("d", 1, $today);
        $working_date = date("Y-m-d", $working_date);
        if (!isWeekend($working_date) && !confirm_holiday(date("Y-m-d", strtotime($working_date))) ) {
            $day_counter++;
        }
        $intCounter++;
        $today  = $working_time;
        if ($intCounter > 1000) {
            //just in case out of control?
            break;
        }
    }

    return $working_date;
}
function isWeekend($check_date) {
    return (date("N",  strtotime($check_date)) > 5);
}
function confirm_holiday($somedate="") {
    if ($somedate=="") {
        $somedate = date("Y-m-d");
    }
    $year = date("Y", strtotime($somedate));
    $blnHoliday = false;
    //newyears
    if ($somedate == observed_day($year, 1, 1)) {
        $blnHoliday = true;
    }
    if ($somedate == format_date($year, 1, 1)) {
        $blnHoliday = true;
    }
    if ($somedate == format_date($year, 12, 31)) {
        $blnHoliday = true;
    }
    //Martin Luther King
    if ($somedate == get_holiday($year, 1, 1, 3)) {
        $blnHoliday = true;
    }
    //President's
    if ($somedate == get_holiday($year, 2, 1, 3)) {
        $blnHoliday = true;
    }
    //easter
    if ($somedate == calculate_easter($year)) {
        $blnHoliday = true;
    }
    //Memorial
    if ($somedate == get_holiday($year, 5, 1)) {
        $blnHoliday = true;
    }
    //july4
    if ($somedate == observed_day($year, 7, 4)) {
        $blnHoliday = true;
    }
    //labor
    if ($somedate == get_holiday($year, 9, 1, 1)) {
        $blnHoliday = true;
    }
    //columbus
    if ($somedate == get_holiday($year, 10, 1, 2)) {
        $blnHoliday = true;
    }
    //thanks
    if ($somedate == get_holiday($year, 11, 4, 4)) {
        $blnHoliday = true;
    }
    //xmas
    if ($somedate == format_date($year, 12, 24)) {
        $blnHoliday = true;
    }
    if ($somedate == format_date($year, 12, 25)) {
        $blnHoliday = true;
    }
    return $blnHoliday;
}

If you need to get how much time was between two dates you can use https://github.com/maximnara/business-days-counter. It's works simply but only with laravel now $diffInSeconds = $this->datesCounter->getDifferenceInSeconds(Carbon::create(2019, 1, 1), Carbon::now(), DateCounter::COUNTRY_FR);

It doesn't counts public holidays and weekends and you can set working interval, for example from 9 to 18 with launch hour or no.

Or if you need just weekends and you use Carbon you can use built in function:

$date1 = Carbon::create(2019, 1, 1)->endOfDay();
$date2 = $dt->copy()->startOfDay();
$diff = $date1->diffFiltered(CarbonInterval::minute(), function(Carbon $date) {
   return !$date->isWeekend();
}, $date2, true);

But it will foreach every minute in interval, for bit intervals it can take a while.

Variant 1:

<?php
/*
 * Does not count current day, the date returned is the last business day
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = time();
    while ($bDays>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6) $bDays--;
    }
    return $timestamp;
}

Variant 2:

<?php
/*
 * Does not count current day, the date returned is a business day 
 * following the last business day
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = time();
    while ($bDays+1>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6) $bDays--;
    }
    return $timestamp;
}

Variant 3:

<?php
/*
 * Does not count current day, the date returned is 
 * a date following the last business day (can be weekend or not. 
 * See above for alternatives)
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = time();
    while ($bDays>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6) $bDays--;
    }
    return $timestamp += 86400;
}

The additional holiday considerations can be made using variations of the above by doing the following. Note! assure all the timestamps are the same time of the day (i.e. midnight).

Make an array of holiday dates (as unixtimestamps) i.e.:

$holidays = array_flip(strtotime('2011-01-01'),strtotime('2011-12-25'));

Modify line :

if (date('N', $timestamp)<6) $bDays--;

to be :

if (date('N', $timestamp)<6 && !isset($holidays[$timestamp])) $bDays--;

Done!

<?php
/*
 * Does not count current day, the date returned is the last business day
 * Requires PHP 5.1 (Using ISO-8601 week)
 */

function businessDays($timestamp = false, $bDays = 2) {
    if($timestamp === false) $timestamp = strtotime(date('Y-m-d',time()));
    $holidays = array_flip(strtotime('2011-01-01'),strtotime('2011-12-25'));
    while ($bDays>0) {
        $timestamp += 86400;
        if (date('N', $timestamp)<6 && !isset($holidays[$timestamp])) $bDays--;
    }
    return $timestamp;
}

calculate workdays between two dates including holidays and custom workweek

The answer is not that trivial - thus my suggestion would be to use a class where you can configure more than relying on simplistic function (or assuming a fixed locale and culture). To get the date after a certain number of workdays you'll:

1. need to specify what weekdays you'll be working (default to MON-FRI) - the class allows you to enable or disable each weekday individually.
2. need to know that you need to consider public holidays (country and state) to be accurate
   • e.g. https://github.com/khatfield/php-HolidayLibrary/blob/master/Holidays.class.php
   • or hardcode the data: e.g. from http://www.feiertagskalender.ch/?hl=en
   • or pay for data-API http://www.timeanddate.com/services/api/holiday-api.html

Functional Approach

/**
 * @param days, int
 * @param $format, string: dateformat (if format defined OTHERWISE int: timestamp) 
 * @param start, int: timestamp (mktime) default: time() //now
 * @param $wk, bit[]: flags for each workday (0=SUN, 6=SAT) 1=workday, 0=day off
 * @param $holiday, string[]: list of dates, YYYY-MM-DD, MM-DD 
 */
function working_days($days, $format='', $start=null, $week=[0,1,1,1,1,1,0], $holiday=[])
{
    if(is_null($start)) $start = time();
    if($days <= 0) return $start;
    if(count($week) != 7) trigger_error('workweek must contain bit-flags for 7 days');
    if(array_sum($week) == 0) trigger_error('workweek must contain at least one workday');
    $wd = date('w', $start);//0=sun, 6=sat
    $time = $start;
    while($days)
    {
        if(
        $week[$wd]
        && !in_array(date('Y-m-d', $time), $holiday)
        && !in_array(date('m-d', $time), $holiday)
        ) --$days; //decrement on workdays
        $wd = date('w', $time += 86400); //add one day in seconds
    }
    $time -= 86400;//include today
    return $format ? date($format, $time): $time;
}

//simple usage
$ten_days = working_days(10, 'D F d Y');
echo '<br>ten workingdays (MON-FRI) disregarding holidays: ',$ten_days;

//work on saturdays and add new years day as holiday
$ten_days = working_days(10, 'D F d Y', null, [0,1,1,1,1,1,1], ['01-01']);
echo '<br>ten workingdays (MON-SAT) disregarding holidays: ',$ten_days;

date_default_timezone_set('America/New_York');


/** Given a number days out, what day is that when counting by 'business' days
  * get the next business day. by default it looks for next business day
  * ie calling  $date = get_next_busines_day(); on monday will return tuesday
  *             $date = get_next_busines_day(2); on monday will return wednesday
  *             $date = get_next_busines_day(2); on friday will return tuesday
  *
  * @param $number_of_business_days (integer)       how many business days out do you want
  * @param $start_date (string)                     strtotime parseable time value
  * @param $ignore_holidays (boolean)               true/false to ignore holidays
  * @param $return_format (string)                  as specified in php.net/date
 */
function get_next_business_day($number_of_business_days=1,$start_date='today',$ignore_holidays=false,$return_format='m/d/y') {

    // get the start date as a string to time
    $result = strtotime($start_date);

    // now keep adding to today's date until number of business days is 0 and we land on a business day
    while ($number_of_business_days > 0) {
        // add one day to the start date
        $result = strtotime(date('Y-m-d',$result) . " + 1 day");

        // this day counts if it's a weekend and not a holiday, or if we choose to ignore holidays
        if (is_weekday(date('Y-m-d',$result)) && (!(is_holiday(date('Y-m-d',$result))) || $ignore_holidays) ) 
            $number_of_business_days--;

    }

    // when my $number of business days is exausted I have my final date

    return(date($return_format,$result));
}

    function is_weekend($date) {
    // return if this is a weekend date or not.
    return (date('N', strtotime($date)) >= 6);
}

function is_weekday($date) {
    // return if this is a weekend date or not.
    return (date('N', strtotime($date)) < 6);
}

function is_holiday($date) {
    // return if this is a holiday or not.

    // what are my holidays for this year
    $holidays = array("New Year's Day 2011" => "12/31/10",
                        "Good Friday" => "04/06/12",
                        "Memorial Day" => "05/28/12",
                        "Independence Day" => "07/04/12",
                        "Floating Holiday" => "12/31/12",
                        "Labor Day" => "09/03/12",
                        "Thanksgiving Day" => "11/22/12",
                        "Day After Thanksgiving Day" => "11/23/12",
                        "Christmas Eve" => "12/24/12",
                        "Christmas Day" => "12/25/12",
                        "New Year's Day 2012" => "01/02/12",
                        "New Year's Day 2013" => "01/01/13"
                        );

    return(in_array(date('m/d/y', strtotime($date)),$holidays));
}


print get_next_business_day(1) . "\n";

Here is another solution without for loop for each day.

$from = new DateTime($first_date);
$to = new DateTime($second_date);

$to->modify('+1 day');
$interval = $from->diff($to);
$days = $interval->format('%a');

$extra_days = fmod($days, 7);
$workdays = ( ( $days - $extra_days ) / 7 ) * 5;

$first_day = date('N', strtotime($first_date));
$last_day = date('N', strtotime("1 day", strtotime($second_date)));
$extra = 0;
if($first_day > $last_day) {
   if($first_day == 7) {
       $first_day = 6;
   }

   $extra = (6 - $first_day) + ($last_day - 1);
   if($extra < 0) {
       $extra = $extra * -1;
   }
}
if($last_day > $first_day) {
    $extra = $last_day - $first_day;
}
$days = $workdays + $extra

Holiday calculation is non-standard in each State. I am writing a bank application which I need some hard business rules for but can still only get a rough standard.

/**
 * National American Holidays
 * @param string $year
 * @return array
 */
public static function getNationalAmericanHolidays($year) {


    //  January 1 - New Year’s Day (Observed)
    //  Calc Last Monday in May - Memorial Day  strtotime("last Monday of May 2011");
    //  July 4 Independence Day
    //  First monday in september - Labor Day strtotime("first Monday of September 2011")
    //  November 11 - Veterans’ Day (Observed)
    //  Fourth Thursday in November Thanksgiving strtotime("fourth Thursday of November 2011");
    //  December 25 - Christmas Day        
    $bankHolidays = array(
          $year . "-01-01" // New Years
        , "". date("Y-m-d",strtotime("last Monday of May " . $year) ) // Memorial Day
        , $year . "-07-04" // Independence Day (corrected)
        , "". date("Y-m-d",strtotime("first Monday of September " . $year) ) // Labor Day
        , $year . "-11-11" // Veterans Day
        , "". date("Y-m-d",strtotime("fourth Thursday of November " . $year) ) // Thanksgiving
        , $year . "-12-25" // XMAS
        );

    return $bankHolidays;
}

There is a Formula:

number_of_days - math_round_down(10 * (number_of_days / (business_days_in_a_week * days_in_a_week)))

Tada! you calculate the numbers of business day, in a month, in a week, in a whatever you want.

math_round_down () is a hypothetical method, which implements a mathematical function that rounds down.

Holiday calculation is non-standard in each State. I am writing a bank application which I need some hard business rules for but can still only get a rough standard.

/**
 * National American Holidays
 * @param string $year
 * @return array
 */
public static function getNationalAmericanHolidays($year) {


    //  January 1 - New Year’s Day (Observed)
    //  Calc Last Monday in May - Memorial Day  strtotime("last Monday of May 2011");
    //  July 4 Independence Day
    //  First monday in september - Labor Day strtotime("first Monday of September 2011")
    //  November 11 - Veterans’ Day (Observed)
    //  Fourth Thursday in November Thanksgiving strtotime("fourth Thursday of November 2011");
    //  December 25 - Christmas Day        
    $bankHolidays = array(
          $year . "-01-01" // New Years
        , "". date("Y-m-d",strtotime("last Monday of May " . $year) ) // Memorial Day
        , $year . "-07-04" // Independence Day (corrected)
        , "". date("Y-m-d",strtotime("first Monday of September " . $year) ) // Labor Day
        , $year . "-11-11" // Veterans Day
        , "". date("Y-m-d",strtotime("fourth Thursday of November " . $year) ) // Thanksgiving
        , $year . "-12-25" // XMAS
        );

    return $bankHolidays;
}