Revisiting Age Calulation / Pre-Epoch Fix too

[libradog]

I've noticed a couple different post addressing age calculation..

here is a simple function I wrote to address the issue:

//--------------------------------------------------
// Age Calculation Function

function ageYearsCalculate($birthday) {

global $ageYears;

$rightNow = date("Ymd");
$ageYears = $rightNow - $birthday;
$ageYears = substr($ageYears, 0, 2);
return($ageYears);
}

Example:

Birthday = 19850612
Today = 20050122

20050122 - 19850612 = 199510
age = substr(199510, 0, 2);
age = 19

20050611 - 19850612 = 199999
20050612 - 19850612 = 200000
20050613 - 19850612 = 200001

Does this seem to make sense?

Can anyone find a fault in this function? It seems to work fine for me, and since its raw math, epoch is not a concern... So birthdays before 1970 work fine as well. The only limitation in the way I have this set up would be people older than 100, but since my form only allows someone to choose a birthday within the last 98 years, it works fine.

A couple previous posts on the subject:
http://phpbuilder.com/board/showthread.php?threadid=10273394&highlight=age+calculation
http://www.phpbuilder.com/board/showthread.php?s=&threadid=10253351&highlight=age#post10410290

[planetsim]

You may find this link helpful http://www.phpbuilder.com/board/showthread.php?s=&threadid=10279939&highlight=age

[Weedpacket]

Then there's the matriarch of my family:

echo ageYearsCalculate('19020911');

Or my friend's son

echo ageYearsCalculate('20021205');