get UTC time in PHP

How can I get UTC/GMT +/- time stamp using PHP's date() function? For example, if I try

date("Y-m-d H:i:s", time()); 

I will get Unix time stamp; but I need to get UTC/GMT time stamp with string GMT/UTC+/-0400 or GMT/UTC+/-1000 based on local timings.

Using gmdate will always return a GMT date. Syntax is same as for date.

A simple gmdate() will suffice

<?php
print gmdate("Y-m-d\TH:i:s\Z");

As previously answered here, since PHP 5.2.0 you can use the DateTime class and specify the UTC timezone with an instance of DateTimeZone.

The DateTime __construct() documentation suggests passing "now" as the first parameter when creating a DateTime instance and specifying a timezone to get the current time.

$date_utc = new \DateTime("now", new \DateTimeZone("UTC"));

echo $date_utc->format(\DateTime::RFC850); # Saturday, 18-Apr-15 03:23:46 UTC

$time = time();
$check = $time+date("Z",$time);
echo strftime("%B %d, %Y @ %H:%M:%S UTC", $check);

Obtaining UTC date

gmdate("Y-m-d H:i:s");

Obtaining UTC timestamp

time();

The result will not be different even you have date_default_timezone_set on your code.