Question

I should be getting exactly 72 hours, but it’s giving me 72 hours and 12 seconds…why???

http://codepad.org/KNj44By5

Answer 1

Because your math is wrong. $elapsed will be in seconds, so you do not need to divide it before taking the modulus. What you are really getting is the modulus of hours % 60.

It will work like this:

$in = strtotime("2011-10-02 23:00:00");
$out = strtotime("2011-10-05 23:00:00"); // 72 hours apart

$elapsed = $out - $in;

$hours = floor($elapsed / 3600);
$minutes = floor(($elapsed / 60) % 60);
   if (strlen($minutes) == "1") { $minutes = "0".$minutes; } // No single digits

$seconds = $elapsed % 60;
   if (strlen($seconds) == "1") { $seconds = "0".$seconds; } // No single digits

$total = $hours.":".$minutes.":".$seconds; // Should be 72:00:00

echo $total

EDIT

You also screwed up your zero-padding. You were turning 2 into 20.

Updated codepad here: http://codepad.org/XY8L9EJ1