A PHP CalculateAge() function created by applying the logic we used previously in C# to calculate the age from a given birth date.

1. <?php
2. // $BirthDate expected format is YYYY/MM/DD
3. function CalculateAge($BirthDate)

4. {

5.        // Put the year, month and day in separate variables
6.        list($Year, $Month, $Day) = explode("/", $BirthDate);
7. 
8.        $YearDiff = date("Y") - $Year;
9. 
10.        // If the birthday hasn't arrived yet this year, the person is 
     one year younger
11.        if(date("m") < $Month || (date("m") == $Month && date("d") < 
     $DayDiff))
12.        {

13.                $YearDiff--;
14.        }

15.        return $YearDiff;
16. }

17. 
18. // How to use the function
19. echo CalculateAge("1986/06/18");
20. ?>