date-math

I'm trying to get the difference between two datetimes and return it as a datetime . I've found examples using diff but I can't seem to get it right. $timein = date("Y-m-d H:i:s"); $timeout = date("Y-m-d 20:00:00"); $totaltime = $timein->diff($timeout); However $totaltime logs 0000-00-00 00:00:00 to my DB. Is this because I'm not formatting my totaltime variable? John Conde I'm not sure what format you're looking for in your difference but here's how to do it using DateTime $datetime1 = new DateTime(); $datetime2 = new DateTime('2011-01-03 17:13:00'); $interval = $datetime1->diff($datetime2);