生年月日から年齢計算

//生年月日から年齢変換
function birthToAge($ymd){
 
	$base  = new DateTime();
	$today = $base->format('Ymd');
 
	$birth    = new DateTime($ymd);
	$birthday = $birth->format('Ymd');
 
	$age = (int) (($today - $birthday) / 10000);
 
	return $age;
}