3v4l.org

run code in 300+ PHP versions simultaneously
<?php $cut = 3600; $date_start = strtotime("2017-11-02 02:19:59"); $date_end = strtotime("2017-11-02 03:32:06"); $total = ($date_end - $date_start) - $cut; if($total < 0){ echo '0'; }else{ echo date("H:i:s", $total); }

preferences:
67.31 ms | 402 KiB | 5 Q