[SOLVED] Calculating birthdate by given age

[john010117]

I already have a method of calculating the age by a given birthdate, but I have no idea how to do that in reverse. Here's my method on calculating the age by given birthdate:

 

<?php
function calculate_age($month, $day, $year) {
global $month, $day, $year;
$time = time();
$new_date = mktime(0, 0, 0, $month, $day, $year);
$age = ($new_date < 0) ? ($time + ($new_date * -1)) : $time - $new_date;
$year = 60 * 60 * 24 * 365;
$return_age = $age / $year;

return floor($return_age);
}
?>

 

But my question is how do you reverse this process so it outputs the birthdate?

[Fadion]

If im getting it right, u have the age of a person (ie. 20) and by that u want to calculate his birthdate (normaly only year). If so then consider the following:

 

<?php
$age = '20';
echo date('Y', strtotime("-$age years")); //it will echo 1987
?>

[john010117]

Ok, thanks.

[Barand]

If all you have is the age in years then the year of birth is as close as you'll get