PHP | Age from date

age_from_date.php

<?php
// Return age in years from date of birth
function get_age( $date_of_birth = 0 ) {
    $age = null;
    if( strtotime( $date_of_birth ) ) {
        $date_today = new DateTime('today');
        $date_of_birth = new DateTime($date_of_birth);
        $age = $date_of_birth->diff($date_today)->y;
    }
    return $age;
}