[java] Double decimal formatting in Java

I'm having some problems formatting the decimals of a double. If I have a double value, e.g. 4.0, how do I format the decimals so that it's 4.00 instead?

I know that this is an old topic, but If you really like to have the period instead of the comma, just save your result as X,00 into a String and then just simply change it for a period so you get the X.00

The simplest way is just to use replace.

String var = "X,00";
String newVar = var.replace(",",".");

The output will be the X.00 you wanted. Also to make it easy you can do it all at one and save it into a double variable:

Double var = Double.parseDouble(("X,00").replace(",",".");

I know that this reply is not useful right now but maybe someone that checks this forum will be looking for a quick solution like this.

First import NumberFormat. Then add this:

NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance();

This will give you two decimal places and put a dollar sign if it's dealing with currency.

import java.text.NumberFormat;
public class Payroll 
{
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) 
    {
    int hoursWorked = 80;
    double hourlyPay = 15.52;

    double grossPay = hoursWorked * hourlyPay;
    NumberFormat currencyFormatter = NumberFormat.getCurrencyInstance();

    System.out.println("Your gross pay is " + currencyFormatter.format(grossPay));
    }

}

There are many way you can do this. Those are given bellow:

Suppose your original number is given bellow:

 double number = 2354548.235;

Using NumberFormat:

NumberFormat formatter = new DecimalFormat("#0.00");
    System.out.println(formatter.format(number));

Using String.format:

System.out.println(String.format("%,.2f", number));

Using DecimalFormat and pattern:

NumberFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
        DecimalFormat decimalFormatter = (DecimalFormat) nf;
        decimalFormatter.applyPattern("#,###,###.##");
        String fString = decimalFormatter.format(number);
        System.out.println(fString);

Using DecimalFormat and pattern

DecimalFormat decimalFormat = new DecimalFormat("############.##");
        BigDecimal formattedOutput = new BigDecimal(decimalFormat.format(number));
        System.out.println(formattedOutput);

In all cases the output will be: 2354548.23

Note:

During rounding you can add RoundingMode in your formatter. Here are some rounding mode given bellow:

    decimalFormat.setRoundingMode(RoundingMode.CEILING);
    decimalFormat.setRoundingMode(RoundingMode.FLOOR);
    decimalFormat.setRoundingMode(RoundingMode.HALF_DOWN);
    decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
    decimalFormat.setRoundingMode(RoundingMode.UP);

Here are the imports:

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

Using String.format, you can do this:

double price = 52000;
String.format("$%,.2f", price);

Notice the comma which makes this different from @Vincent's answer

Output:

$52,000.00

A good resource for formatting is the official java page on the subject

You could always use the static method printf from System.out - you'd then implement the corresponding formatter; this saves heap space in which other examples required you to do.

Ex:

System.out.format("%.4f %n", 4.0); 

System.out.printf("%.2f %n", 4.0); 

Saves heap space which is a pretty big bonus, nonetheless I hold the opinion that this example is much more manageable than any other answer, especially since most programmers know the printf function from C (Java changes the function/method slightly though).

With Java 8, you can use format method..: -

System.out.format("%.2f", 4.0); // OR

System.out.printf("%.2f", 4.0); 

• f is used for floating point value..
• 2 after decimal denotes, number of decimal places after .

For most Java versions, you can use DecimalFormat: -

    DecimalFormat formatter = new DecimalFormat("#0.00");
    double d = 4.0;
    System.out.println(formatter.format(d));

You can use any one of the below methods

1. If you are using java.text.DecimalFormat

   DecimalFormat decimalFormat = NumberFormat.getCurrencyInstance(); 
   decimalFormat.setMinimumFractionDigits(2); 
   System.out.println(decimalFormat.format(4.0));
   

   OR

   DecimalFormat decimalFormat =  new DecimalFormat("#0.00"); 
   System.out.println(decimalFormat.format(4.0)); 
   

2. If you want to convert it into simple string format

   System.out.println(String.format("%.2f", 4.0)); 
   

All the above code will print 4.00

new DecimalFormat("#0.00").format(4.0d);

You can do it as follows:

double d = 4.0;
DecimalFormat df = new DecimalFormat("#.##");
System.out.print(df.format(d));

Use String.format:

String.format("%.2f", 4.52135);

As per docs:

The locale always used is the one returned by Locale.getDefault().

double d = 4.0;
DecimalFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
System.out.println(nf.format("#.##"));

An alternative method is use the setMinimumFractionDigits method from the NumberFormat class.

Here you basically specify how many numbers you want to appear after the decimal point.

So an input of 4.0 would produce 4.00, assuming your specified amount was 2.

But, if your Double input contains more than the amount specified, it will take the minimum amount specified, then add one more digit rounded up/down

For example, 4.15465454 with a minimum amount of 2 specified will produce 4.155

NumberFormat nf = NumberFormat.getInstance();
nf.setMinimumFractionDigits(2);
Double myVal = 4.15465454;
System.out.println(nf.format(myVal));

Try it online

Works 100%.

import java.text.DecimalFormat;

public class Formatting {

    public static void main(String[] args) {
        double value = 22.2323242434342;
        // or  value = Math.round(value*100) / 100.0;

        System.out.println("this is before formatting: "+value);
        DecimalFormat df = new DecimalFormat("####0.00");

        System.out.println("Value: " + df.format(value));
    }

}