- var_dump: documentation ( source)
- date_default_timezone_set: documentation ( source)
- date: documentation ( source)
<?php
date_default_timezone_set('Europe/Berlin');
$birthday = new DateTime('1990-09-23 22:09');
$today = new DateTime();
if (date('I') == 0)
$today->add(new DateInterval('PT1H'));
$age = $birthday->diff($today, true);
var_dump($age);