- date: documentation ( source)
- strtotime: documentation ( source)
<?php
$ts1 = strtotime(date('Y-m-d H:i:s'));
$ts2 = strtotime('2014-05-06 14:20:06');
$seconds_diff = $ts1 - $ts2;
$iNbDaysNotedAfterBuyingProject = ($seconds_diff/3600/ 24);
echo $iNbDaysNotedAfterBuyingProject;