- mktime: documentation ( source)
- floor: documentation ( source)
<?php
// Get current time
$date1 = mktime(10,0,0,07,01,2014);
// Get the timestamp of 2006 October 20
$date2 = mktime(05,0,0,07,05,2014);
$dateDiff = $date1 - $date2;
$fullDays = floor($dateDiff/(60*60*24));
echo "Differernce is $fullDays days";