From: Clifford Heath <no@...>
Date: 2007-03-15T01:10:05+09:00
Subject: Re: Calculating the age given DOB

Brian Adkins wrote:
> (DateTime.now - birthdate) / 365.25

That's not very reliable. There are algorithms that calculate
the number of days since some epoch from a date, and the
reverse, based on Fortran code that was posted in the CACM
sometime around 1970. I have a copy somewhere, but there
must be a modern version already in Ruby. If you can't
find a way, I'll dig out mine.

Just convert both dates to days-since-epoch and subtract.

Clifford.