Question

I am trying to write a function that will add time stamps together to get a sum of all. For example:11:30 + 12:00 + 15:35 = 39:05 I am unsure of how to accomplish this. I have included code below that I have tried but it does not give the desired result:

$TotalTime = strtotime($data['TotalSunday']) + strtotime($data['TotalMonday']) 
    + strtotime($data['TotalTuesday'])
    + strtotime($data['TotalWednesday'])    + strtotime($data['TotalThursday'])
    + strtotime($data['TotalFriday']) + strtotime($data['TotalSaturday']);
    $data['TotalTime'] = gmdate("h:i", $TotalTime);

Answer 1

The problem is the following, you do want to add “times”, but in fact you are creating the sum of “dates”. strtotime expects two parameters: #1 is a date, #2 is a offset (if not given, it is “now”).

This is merely a hack, and I’m not sure if anyone would use it like that, but it works:

<?php

    $time1 = strtotime("00:25Z", 0);
    $time2 = strtotime("23:20:05Z", 0);

    $sumTime = $time1 + $time2;

    $hours = $sumTime / 3600;
    $minutes = ($sumTime % 3600) / 60;

    echo sprintf("%d:%d", $hours, $minutes); // Outputs: 23:45

?>

By setting the second parameter to 0, and providing the datetime parameter with an additional Z (for Zulu time, or UTC), times up to 23:59:59 are parsed correctly in seconds.

So if you really want to rely on strtotime, use it like that.