- var_dump: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
$from = new DateTime(date('Y-m-d 00:00:00', strtotime("2016-10-19 22:00:00")));
$to = new DateTime(date('Y-m-d 00:00:00', strtotime("today")));
var_dump($to->diff($from)->format('%a'));