PHP: Convert Local Time to UTC

Question

Assume I get a string like 08/22/2015 10:56 PM and that this date/time string always refers to only one particular time zone. I need to be able to convert that to t

Answer 1

according to subject line; To convert local time to UTC you need the timezone name of given local time, or if you have timezone offset in GMT; you can try the following:

//assume time zone is +3 hours
$offset = 3 * 60 * 60;
$date = date('H:i:s', strtotime("10:56 PM")- $offset);
echo $date;

This will output : 19:56:00 which is UTC Time

Answer 2

You can use DateTime, example bellow:

<?php

$datetime = '08/22/2015 10:56 PM';
$tz_from = 'America/New_York';
$tz_to = 'UTC';
$format = 'Ymd\THis\Z';

$dt = new DateTime($datetime, new DateTimeZone($tz_from));
$dt->setTimeZone(new DateTimeZone($tz_to));
echo $dt->format($format) . "\n";

$minutes = 30;
$dt->add(new DateInterval('PT' . $minutes . 'M'));
echo $dt->format($format) . "\n";