Wicked Cool PHP

#49: Finding the Difference Between Two Dates

If you find yourself in a situation where you need to know how much time has elapsed between a pair of dates, here's what you're looking for.

<?php

function calculate_time_difference($timestamp1, $timestamp2, $time_unit) {
    // Determines difference between two timestamps

    $timestamp1 = intval($timestamp1);
    $timestamp2 = intval($timestamp2);
    if ($timestamp1 && $timestamp2) {
        $time_lapse = $timestamp2 - $timestamp1;

        $seconds_in_unit = array(

          'second'   => 1,
          'minute'   => 60,
          'hour'     => 3600,
          'day'      => 86400,
          'week'     => 604800,
        );
   
        if ($seconds_in_unit[$time_unit]) {
            return floor($time_lapse/$seconds_in_unit[$time_unit]);
        }
    }
    return false;
}
?>

The calculate_time_difference() function takes three arguments: the ...