Calculate two dates with PHP?

Question

I have two dates in the format below:

Start Date = 30-10-2009

End Date = 30-11-2009

How, with PHP could I calculate the seconds between these two dates?

Answer 1

The function strtotime() will convert a date to a unix-style timestamp (in seconds). You should then be able to subtract the end date from the start date to get the difference.

$difference_secs = strtotime($end_date) - strtotime($start_date);

Answer 2

Parse the two dates into Unix timestamps using strtotime, then get the difference:

$firstTime = strtotime("30-10-2009");
$secondTime = strtotime("30-11-2009");
$diff = $secondtime - $firstTime;

Answer 3

I'd rather advice to use built in DateTime object.

$firstTime = new DateTime("30-10-2009");
$diff = $firstTime->diff(new DateTime("30-11-2009"));

As for me it's more flexible and OOP oriented.