how do I get the difference between 2 date?

[shelbytll]

Hi,

how do I get the difference between 2 date?
for example if I have a birth date, I would like to get the person's age by subtracting today date and that birth date.

[jowatkins]

function get_date_diff($datefrom, $dateto)
{
$numSecondsInDay = 86400;
$Difference = $dateto-$datefrom;
$DifferenceInDays = intval($Difference/$numSecondsInDay);
return $DifferenceInDays;
}

dates need to be converted to unix format first.

$UnixDate = mktime(0,0,0,"$Month","$Day","$Year");