- date_default_timezone_set: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
$end_date = "2014-09-09 15:03:10";
date_default_timezone_set('Asia/Calcutta');
$now = date('Y-m-d H:i:s');
echo strtotime($now) - strtotime($end_date);