PHP将本地时间转换为UTC DateTime

Question

I want to convert my local timezone dateTime to UTC timezone DateTime.

date_default_timezone_set('Asia/Calcutta');
$datetime = "2016-05-05 18:33:00";
echo date_default_timezone_get()."<br>"; // Asia/Calcutta
date_default_timezone_set('UTC');
echo date_default_timezone_get()."<br>"; //UTC
echo $utcDateTime = date("Y-m-d H:i:s",strtotime($datetime));

Current Output

2016-05-05 18:33:00

But, Problem is do not convert local dateTime to UTC dateTime. It will give output as Local DateTime.

Answer 1

You will need to pass the date to strtotime before you change the timezone with date_default_timezone_set. Like so:

date_default_timezone_set('Asia/Calcutta');
$datetime = "2016-05-05 18:33:00";
$asia_timestamp = strtotime($datetime);
echo date_default_timezone_get()."<br>"; // Asia/Calcutta
date_default_timezone_set('UTC');
echo date_default_timezone_get()."<br>"; //UTC
echo $utcDateTime = date("Y-m-d H:i:s", $asia_timestamp);