Calculate Number of hours worked in 2 24 hour time format PHP

Question

Hi I have a two variable in 24 hour time format and want to compute the number of hours worked. But I get negative and wrong value

I'm using PHP and here's my code

$endtime = date( 'g:i A', strtotime( $itInfo['endTime'] ) );
$startTime = date( 'g:i A', strtotime( $itInfo['startTime'] ) );
$timeDiff = (strtotime($endtime) - strtotime($startTime))/60/60;
$total      = strtotime($endtime) - strtotime($startTime);
$hours      = floor($total / 60 / 60);
$minutes    = round(($total - ($hours * 60 * 60)) / 60);

echo "FROM ".$itInfo['startTime']." TO ".$itInfo['endTime']." (".$hours.'.'.$minutes."hours)";`

Here's the output FROM 22:00 TO 03:00 (-19.0hours) which is wrong the output should be 5 Hours.

possible duplicate of [Calculate number of hours between 2 dates in PHP](http://stackoverflow.com/questions/3108591/calculate-number-of-hours-between-2-dates-in-php) — Hytool, Jul 20 '15 at 03:40
No. I'm saving it as varchar with this format HH:MM in 24 hours — jc premiere, Jul 20 '15 at 03:42
You really should work with timestamps (`time();`) internally. — Ole Sauffaus, Jul 20 '15 at 03:59

score 0 · Accepted Answer · answered Jul 20 '15 at 04:07

0

Try this:

$timeDiff = strtotime($itInfo['endTime']) - strtotime($itInfo['startTime']);

echo substr('00'.($timeDiff / 3600 % 24),-2)
    .':'. substr('00'.($timeDiff / 60 % 60),-2)
    .':'. substr('00'.($timeDiff % 60),-2);

answered Jul 20 '15 at 04:07

Ole Sauffaus

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score 0 · Answer 2 · answered Jul 20 '15 at 04:15

0

As others have stated, best to work with timestamps. But with your current code, you should be able to add this right before the echo:

if ($itInfo['startTime'] > $itInfo['endTime']) {
    $hours = 24 - $hours;
}

This would be: 24 - 19 = 5.

Also, be sure to take add abs() in your $total variable as well:

$total = abs(strtotime($endtime) - strtotime($startTime));

answered Jul 20 '15 at 04:15

camelCase

5,460
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Don't use `abs()`, as that will mask potential errors from faulty input-values ... – Ole Sauffaus Jul 20 '15 at 04:20
Interesting point, thanks! Can you give an example of how so? – camelCase Jul 20 '15 at 04:32
If the calculated difference comes out negative (which should NEVER happen), `abs()` will make it positive ... and you may have a hard time figuring out, what went wrong. – Ole Sauffaus Jul 20 '15 at 04:35

Calculate Number of hours worked in 2 24 hour time format PHP

2 Answers2