php convert datetime to UTC

Use strtotime to generate a timestamp from the given string (interpreted as local time) and use gmdate to get it as a formatted UTC date back.

Example

As requested, here’s a simple example:

echo gmdate('d.m.Y H:i', strtotime('2012-06-28 23:55'));

Try the getTimezone and setTimezone, see the example

(But this does use a Class)

UPDATE:

Without any classes you could try something like this:

$the_date = strtotime("2010-01-19 00:00:00");
echo(date_default_timezone_get() . "<br />");
echo(date("Y-d-mTG:i:sz",$the_date) . "<br />");
echo(date_default_timezone_set("UTC") . "<br />");
echo(date("Y-d-mTG:i:sz", $the_date) . "<br />");

NOTE: You might need to set the timezone back to the original as well

If you have a date in this format YYYY-MM-HH dd:mm:ss, you can actually trick php by adding a UTC at the end of your "datetime string" and use strtotime to convert it.

date_default_timezone_set('Europe/Stockholm');
print date('Y-m-d H:i:s',strtotime("2009-01-01 12:00"." UTC"))."\n";
print date('Y-m-d H:i:s',strtotime("2009-06-01 12:00"." UTC"))."\n";

This will print this:

2009-01-01 13:00:00
2009-06-01 14:00:00

And as you can see it takes care of the daylight savings time problem as well.

A little strange way to solve it.... :)

If you don't mind using PHP's DateTime class, which has been available since PHP 5.2.0, then there are several scenarios that might fit your situation:

1. If you have a $givenDt DateTime object that you want to convert to UTC then this will convert it to UTC:

   $givenDt->setTimezone(new DateTimeZone('UTC'));
   

2. If you need the original $givenDt later, you might alternatively want to clone the given DateTime object before conversion of the cloned object:

   $utcDt = clone $givenDt;
   $utcDt->setTimezone(new DateTimeZone('UTC'));
   

3. If you only have a datetime string, e.g. $givenStr = '2018-12-17 10:47:12', then you first create a datetime object, and then convert it. Note this assumes that $givenStr is in PHP's configured timezone.

   $utcDt = (new DateTime($givenStr))->setTimezone(new DateTimeZone('UTC'));
   

4. If the given datetime string is in some timezone different from the one in your PHP configuration, then create the datetime object by supplying the correct timezone (see the list of timezones PHP supports). In this example we assume the local timezone in Amsterdam:

   $givenDt = new DateTime($givenStr, new DateTimeZone('Europe/Amsterdam'));
   $givenDt->setTimezone(new DateTimeZone('UTC'));
   

I sometime use this method:

// It is not importnat what timezone your system is set to.
// Get the UTC offset in seconds:
$offset = date("Z");

// Then subtract if from your original timestamp:
$utc_time = date("Y-m-d H:i:s", strtotime($original_time." -".$offset." Seconds"));

Works all MOST of the time.

http://php.net/manual/en/function.strtotime.php or if you need to not use a string but time components instead, then http://us.php.net/manual/en/function.mktime.php

alternatively you can try this:

<?php echo (new DateTime("now", new DateTimeZone('Asia/Singapore')))->format("Y-m-d H:i:s e"); ?>

this will output :

2017-10-25 17:13:20 Asia/Singapore

you can use this inside the value attribute of a text input box if you only want to display a read-only date.

remove the 'e' if you do not wish to show your region/country.

Follow these steps to get UTC time of any timezone set in user's local system (This will be required for web applications to save different timezones to UTC):

1. Javascript (client-side):

   var dateVar = new Date();
   var offset = dateVar.getTimezoneOffset();
   //getTimezoneOffset - returns the timezone difference between UTC and Local Time
   document.cookie = "offset="+offset;
   

2. Php (server-side):

   public function convert_utc_time($date)
   {
       $time_difference = isset($_COOKIE['offset'])?$_COOKIE['offset']:'';
       if($time_difference != ''){
           $time = strtotime($date);
           $time = $time + ($time_difference*60); //minutes * 60 seconds
           $date = date("Y-m-d H:i:s", $time);
       } //on failure of js, default timezone is set as UTC below
       return $date;
   }
   ..
   ..
   //in my function
   $timezone = 'UTC';
   $date = $this->convert_utc_time($post_date); //$post_date('Y-m-d H:i:s')
   echo strtotime($date. ' '. $timezone)