- date_default_timezone_set: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
date_default_timezone_set('Europe/London');
$date = new DateTime();
$A = $date->format('Y-m-d H:i:s');
$date->modify("+64 minutes");
$B = $date->format('Y-m-d H:i:s');
echo date('h:i T', strtotime($B) - strtotime($A));