finding out the age from a birthdate

Hi there, i am somehow strugling to find out how to get the age of a person from its birthdate. If I divide the date from today, there still is a year instead of the age. And deviding the years does not work since we should be accurat about the day. I tried: $age[] = date("Y",(time()-$birthday)); (where birthday is a unix timestamp) Has anybody an idea how to do that? Thanx, Merlin