PHP calculate person's current age

Question

I have birth dates on my site in format 12.01.1980.

$person_date (string) = Day.Month.Year

Want to add an oldness of the person. Like "Currently 30 years" (2010 - 1980 = 30 years).

But makin the function just on years can't give the perfect result:

If person birth date is 12.12.1980 and current date is 01.01.2010 the person doesn't have 30 years old. It's a 29 years and one month.

There must be a calculation on targeting both year, month and day of birth with comparison of current date:

0) Parse the dates.

Birth date (Day.Month.Year):
Day = $birth_day;
Month = $birth_month;
Year = $birth_year;

Current date (Day.Month.Year):
Day = $current_day;
Month = $current_month;
Year = $current_year;

1) year comparison, 2010 - 1980 = write "30" (let it be $total_year variable)

2) compare the months, if (birth date month is bigger > than current month (like 12 in birth and 01 current)) { do minus one year from $total_year variable (30 - 1 = 29) }. If do minus happened, finish the calculations at this point. Else go the next (3 step).

3) else if (birth month < current month) { $total_year = $total_year (30); }

4) else if (birth month = current month) { $total_year = $total_year (30); }

and check the day (in this step):

 if(birth day = current day) { $total_year = $total_year; }
 else if (birth day > current day) { $total_year = $total_year -1; }
 else if (birth day < current day) { $total_year = $total_year; }

5) echo $total_year;

My php knowledge isn't good, hope you can help.

Thanks.

Answer 1

You can use the DateTime class and its diff() method.

<?php
$bday = new DateTime('12.12.1980');
// $today = new DateTime('00:00:00'); - use this for the current date
$today = new DateTime('2010-08-01 00:00:00'); // for testing purposes

$diff = $today->diff($bday);

printf('%d years, %d month, %d days', $diff->y, $diff->m, $diff->d);

prints 29 years, 7 month, 20 days