PHP: Timestamp difference incorrect

The situation

I've got two timestamps.

One with the start time and one with the end time.

The start time is: 04:43:37

The end time is: 11:59:59

Now I am trying to get the differen开发者_如何学Goce between the dates like this:

//define timestamps
$start_time     = 1297698217;
$end_time      = 1297724399;
$time_diff    = $end_time - $start_time;

//display times and difference
echo 
    '<b>Start time:</b> ' . date('d-m-Y h:i:s', $start_time) . '<br />' .
    '<b>End time:</b> ' . date('d-m-Y h:i:s', $end_time) . '<br />' .
    '<b>Time difference::</b> ' . date('h:i:s', $time_diff);

The result

Start time: 14-02-2011 04:43:37
End time: 14-02-2011 11:59:59
Time difference: 08:16:22

The problem

Now the problem is that the result should be 07:16:22. I've tried this with different times, but every time I'm getting the same result. One hour too much difference.

Is there an expert willing to help?

The last one should be gmdate instead of date:

'<b>Time difference::</b> ' . gmdate('h:i:s', $time_diff);

date adjusts for your current locale, which appears to be GMT+1. gmdate does not make that adjustment.

I'm assuming that you're only planning to use this for time differences less than 24 hours.

You're asking it to turn 1970-01-01 07:16:22 into a time string for display - there are going to be differences based on your time zone.

To make it a GMT date use gmdate() but this will still cause you issues when time differences get >24 hours.