- var_dump: documentation ( source)
<?php
$date1 = new DateTime("1970-01-01", new DateTimeZone("Europe/Frankfurt"));
$date2 = new DateTime("2015-10-26", new DateTimeZone("Europe/Frankfurt"));
$diff = $date2->diff($date1, true);
var_dump($diff->y * 8760 + $diff->m * 730 + $diff->d * 24 + $diff->h);