php convert datetime to UTC

Question

I am in need of an easy way to convert a date time stamp to UTC (from whatever timezone the server is in) HOPEFULLY without using any libraries.

Answer 1

try

echo date('F d Y', strtotime('2010-01-19 00:00:00'));

will output:

January 19 2010

you should change format time to see other output

Answer 2

Do this way:

gmdate('Y-m-d H:i:s', $timestamp)

or simply

gmdate('Y-m-d H:i:s')

to get "NOW" in UTC.

Check the reference:

http://www.php.net/manual/en/function.gmdate.php

Answer 3

Convert local time zone string to UTC string.
e.g. New Zealand Time Zone

$datetime = "2016-02-01 00:00:01";
$given = new DateTime($datetime, new DateTimeZone("Pacific/Auckland"));
$given->setTimezone(new DateTimeZone("UTC"));
$output = $given->format("Y-m-d H:i:s"); 
echo ($output);

• NZDT: UTC+13:00
  if $datetime = "2016-02-01 00:00:01", $output = "2016-01-31 11:00:01";
  if $datetime = "2016-02-29 23:59:59", $output = "2016-02-29 10:59:59";
  
• NZST: UTC+12:00
  if $datetime = "2016-05-01 00:00:01", $output = "2016-04-30 12:00:01";
  if $datetime = "2016-05-31 23:59:59", $output = "2016-05-31 11:59:59";
  

https://en.wikipedia.org/wiki/Time_in_New_Zealand

Answer 4

As strtotime requires specific input format, DateTime::createFromFormat could be used (php 5.3+ is required)

// set timezone to user timezone
date_default_timezone_set($str_user_timezone);

// create date object using any given format
$date = DateTime::createFromFormat($str_user_dateformat, $str_user_datetime);

// convert given datetime to safe format for strtotime
$str_user_datetime = $date->format('Y-m-d H:i:s');

// convert to UTC
$str_UTC_datetime = gmdate($str_server_dateformat, strtotime($str_user_datetime));

// return timezone to server default
date_default_timezone_set($str_server_timezone);