Age Calculator (PHP)

function calculate_age($dob='01/01/1900') {//MM/DD/YYYY
    $dob = str_replace('-', explode('/', $dob));
    $mk = mktime(0, 0, 0, $dob[0], $dob[1], $dob[2]);
    return (date('md',date('U',$mk))>date('md')?((date('Y')-$dob[2])-1):(date('Y')-$dob[2]));
}