How can I convert a date to GMT

Question

How to convert date of different timezones to GMT 0  Let say I have dates like this  Fri Jan 20 2012 11 51 36 GMT-0500 Fri Jan 20 2012 11 51 36 GMT-0300 Fri Jan 20 2012 11 51 36 GMT 0500   to   Fri Jan 20 2012 06 51 36 GMT Fri Jan 20 2012 08 51 36 GMT Fri Jan 20 2012 16 51 36 GMT   these are dates I am getting via new Date   toString   on different timezones  Is there any js method to detect timezone and convert accordingly   EDIT  The second three dates are not the GMT converted times of the first three  For example  Fri Jan 20 2012 11 51 36 GMT-0500 in GMT is Fri Jan 20 2012 16 51 36 GMT not Fri Jan 20 2012 06 51 36 GMT  GMT-0500 is behind GMT  not ahead  so you have to add the offset to get GMT  not subtract it

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Simply use Date getUTC    family of methods  On my computer  CET  UTC 01 00    new Date   toString     Fri Jan 20 2012 18 05 16 GMT 0100  CET   new Date   getHours     18  new Date   getUTCHours     17   Notice that getUTCHours   returns correct hour in UTC   See also    Annoying javascript timezone adjustment issue

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I am trying with the below  This seems to be working fine  Are there any limitations to this approach  Please confirm   var now new Date                               Sun Apr 02 2017 2 00 00 GMT 1000  AEST  var gmtRe    GMT   -     d 4     var tz   gmtRe exec now  1                     1000 var hour tz 100                               10 var min tz 100                                0 now setHours now getHours  -hour   now setMinutes now getMinutes  -min           Sat Apr 01 2017 16 00 00 GMT

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I was just working on this  I may be a bit late   but I did a workaround   Here are steps    - Get current time from whatever timezone the app is fired -  - Get time zone offset of that zone from gmt 0  then add your timezone value in     miliseconds   You will get the date in your time zone  I added some extra code to remove anything after the actual time   getCurrentDate         var date   new Date        var newDate   new Date 8   60   60000   date valueOf                                  date getTimezoneOffset     60000        var ampm   newDate getHours    lt  12     AM      PM       var strDate   newDate           return  strDate  substring 0  strDate indexOf   GMT      ampm

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After searching for an hour or two  I ve found a simple solution below   const date   new Date    date from client  GMT         inside double ticks  there is a date from client side plust GMT    I m first time commenting  constructive criticism will be welcomed

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Although it looks logical  the accepted answer is incorrect because JavaScript dates don t work like that   It s super important to note here that the numerical value of a date  i e   new Date  -0 or Date now    in JavaScript is always measured as millseconds since the epoch which is a timezone-free quantity based on a precise exact instant in the history of the universe  You do not need to add or subtract anything to the numerical value returned from Date   to convert the numerical value into a timezone  because the numerical value has no timezone  If it did have a timezone  everything else in JavaScript dates wouldn t work   Timezones  leap years  leap seconds  and all of the other endlessly complicated adjustments to our local times and dates  are based on this consistent and unambiguous numerical value  not the other way around   Here are examples of how the numerical value of a date  provided to the date constructor  is independent of timezone   In Central Standard Time   new Date 0      Wed Dec 31 1969 18 00 00 GMT-0600  CST    In Anchorage  Alaska   new Date 0      Wed Dec 31 1969 15 00 00 GMT-0900  AHST    In Paris  France   new Date 0      Thu Jan 01 1970 01 00 00 GMT 0100  CET    It is critical to observe that in ALL cases  based on the timezone-free epoch offset of zero milliseconds  the resulting time is identical  1 am in Paris  France is the exact same moment as 3 pm the day before in Anchorage  Alaska  which is the exact same moment as 6 pm in Chicago  Illinois   For this reason  the accepted answer on this page is incorrect  Observe      Create a date     date   new Date       Fri Jan 27 2017 18 16 35 GMT-0600  CST       Observe the numerical value of the date     date valueOf       1485562595732    n b  this value has no timezone and does not need one        Observe the incorrectly  corrected  numerical date value     date valueOf     date getTimezoneOffset     60000     1485584195732      Try out the incorrectly  converted  date string     new Date date valueOf     date getTimezoneOffset     60000      Sat Jan 28 2017 00 16 35 GMT-0600  CST      Not the correct result even within the same script          If you have a date string in another timezone  no conversion to the resulting object created by new Date  date string   is needed  Why  JavaScript s numerical value of that date will be the same regardless of its timezone  JavaScript automatically goes through amazingly complicated procedures to extract the original number of milliseconds since the epoch  no matter what the original timezone was   The bottom line is that plugging a textual date string x into the new Date x  constructor will automatically convert from the original timezone  whatever that might be  into the timezone-free epoch milliseconds representation of time which is the same regardless of any timezone  In your actual application  you can choose to display the date in any timezone that you want  but do NOT add subtract to the numerical value of the date in order to do so  All the conversion already happened at the instant the date object was created  The timezone isn t even there anymore  because the date object is instantiated using a precisely-defined and timezone-free sense of time   The timezone only begins to exist again when the user of your application is considered  The user does have a timezone  so you simply display that timezone to the user  But this also happens automatically   Let s consider a couple of the dates in your original question      date1   new Date  Fri Jan 20 2012 11 51 36 GMT-0300       Fri Jan 20 2012 08 51 36 GMT-0600  CST       date2   new Date  Fri Jan 20 2012 11 51 36 GMT-0300      Fri Jan 20 2012 08 51 36 GMT-0600  CST    The console already knows my timezone  and so it has automatically shown me what those times mean to me   And if you want to know the time in GMT UTC representation  also no conversion is needed  You don t change the time at all  You simply display the UTC string of the time       date1 toUTCString        Fri  20 Jan 2012 14 51 36 GMT    Code that is written to convert timezones numerically using the numerical value of a JavaScript date is almost guaranteed to fail  Timezones are way too complicated  and that s why JavaScript was designed so that you didn t need to

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After searching for an hour or two  I ve found a simple solution below   const date   new Date    date from client  GMT         inside double ticks  there is a date from client side plust GMT    I m first time commenting  constructive criticism will be welcomed

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Update   Matt Johnsons answer is much better than this one was   new Date  Fri Jan 20 2012 11 51 36 GMT-0500   toUTCString     https   stackoverflow com a 26454317 334274

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You can simply use the toUTCString   or toISOString  methods of the date object   Example   new Date  Fri Jan 20 2012 11 51 36 GMT-0500   toUTCString       Output    Fri  20 Jan 2012 16 51 36 GMT    If you prefer better control of the output format  consider using a library such as date-fns or moment js   Also  in your question  you ve actually converted the time incorrectly   When an offset is shown in a timestamp string  it means that the date and time values in the string have already been adjusted from UTC by that value    To convert back to UTC  invert the sign before applying the offset   11 51 36 -0300      14 51 36Z

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GMTDate   new Date   toGMTString

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Based on the accepted answer and the second highest scoring answer both are not perfect according to the comment so I mixed both to get something perfect    x000D   x000D  var date   new Date      Current timestamp x000D  date   date toGMTString     x000D    Based on the time zone where the date was created x000D  console log date   x000D   x000D    based on the comment getTimezoneOffset returns an offset based  x000D  on the date it is called on  and the time zone of the computer the code is x000D   running on  It does not supply the offset passed in when constructing a  x000D  date from a string     x000D   x000D  date   new Date date     will convert to present timestamp offset x000D  date   new Date date getTime      date getTimezoneOffset     60   1000     x000D  console log date   x000D   x000D   x000D

[javascript] How can I convert a date to GMT?

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