How to convert a decimal into time, eg. HH:MM:SS

Question

I am trying to take a decimal and convert it so that I can echo it as hours, minutes, and seconds.

I have the hours and minutes, but am breaking my brain trying to find the seconds. Been googling for awhile with no luck. I'm sure it is quite simple, but nothing I have tried has worked. Any advice is appreciated!

Here is what I have:

function convertTime($dec)
{
    $hour = floor($dec);
    $min = round(60*($dec - $hour));
}

Like I said, I get the hour and minute without issue. Just struggling to get seconds for some reason.

Thanks!

what you have doesn't seem right also. Can you provide a sample input and expected output ? — Sorin, Feb 01 '12 at 20:22
possible duplicate of [How to Convert decimal number to time or vice versa](http://stackoverflow.com/questions/1345599/how-to-convert-decimal-number-to-time-or-vice-versa) — Gordon, Feb 01 '12 at 20:24
Also, the output is expected to just be a number for hour, a number for min, and a number for sec that I can then use to print a HTML page. — HMFlol, Feb 01 '12 at 20:24
the possible duplicate is tagged c# but there is an answer with the general formula for converting decimal time to regular — Gordon, Feb 01 '12 at 20:24
Sorry. Yes the number represents hours. And this is not a duplicate. The post you linked to converts to hours and minutes, which I already do. I was having issue with the getting seconds. — HMFlol, Feb 01 '12 at 20:26

WWW · Accepted Answer · 2015-06-25T16:59:11.250

26

If $dec is in hours ($dec since the asker specifically mentioned a decimal):

function convertTime($dec)
{
    // start by converting to seconds
    $seconds = ($dec * 3600);
    // we're given hours, so let's get those the easy way
    $hours = floor($dec);
    // since we've "calculated" hours, let's remove them from the seconds variable
    $seconds -= $hours * 3600;
    // calculate minutes left
    $minutes = floor($seconds / 60);
    // remove those from seconds as well
    $seconds -= $minutes * 60;
    // return the time formatted HH:MM:SS
    return lz($hours).":".lz($minutes).":".lz($seconds);
}

// lz = leading zero
function lz($num)
{
    return (strlen($num) < 2) ? "0{$num}" : $num;
}

edited Jun 25 '15 at 16:59

answered Feb 01 '12 at 20:27

WWW

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Thanks for the help. That makes more sense than what I was trying to do. :) – HMFlol Feb 01 '12 at 20:43
4

Instead of creating the `lz` function, you can use the native `str_pad` function, from PHP: `str_pad($num, 2, 0, STR_PAD_LEFT)` – elboletaire Sep 08 '13 at 18:53
@elboletaire Very true, I just happened to rip this out of some old, old class of mine. – WWW Sep 09 '13 at 13:41
Just a note: I don't agree with the community edit made adding the explicit `(int)` cast to that first line of the `convertTime()` function. The edit note said something about casting `$dec` as an `(int)` for rounding - if you want to round off the seconds, just use `round()` in the appropriate place. – WWW Jan 21 '14 at 15:44
2

In fact, since the asker specifically asked about a *decimal*, I removed the `(int)` cast. Doesn't make much sense to truncate the hours variable and yet still do minute and second calculations (since if you round the hours variable, there won't **be** any minutes or seconds!) – WWW Jun 25 '15 at 17:00

score 16 · Answer 2 · answered Feb 01 '12 at 20:29

16

Very simple solution in one line:

echo gmdate('H:i:s', floor(5.67891234 * 3600));

answered Feb 01 '12 at 20:29

Cheery

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@Crontab Did not think about it :) Thanks. – Cheery Feb 01 '12 at 20:44
3

Does it matter if you use `date()` instead of `gmdate()`? – Staysee Dec 04 '14 at 15:55
@Staysee decimal time, as timestamp, as I think, defined in UTC timezone. Otherwise it will be shifted to the server's timezone and you may never get, for example, 0 and so on. – Cheery Dec 04 '14 at 18:47
how can i convert 17:30 -> 17.5 – saber tabatabaee yazdi May 20 '19 at 18:52
1

@sabertabatabaeeyazdi like this, for example `$time = strtotime('17:30') - strtotime('midnight'); echo $time / 3600;` – Cheery May 20 '19 at 22:34
3

Caution: If you had a number of hours greater than one day in decimal (e.g. a stopwatch) and wanted hours:minutes this would loop round as it will never read more than 24. – Paul Feakins Dec 15 '20 at 14:52

score 5 · Answer 3 · answered Oct 28 '16 at 09:06

5

Everything upvoted didnt work in my case. I have used that solution to convert decimal hours and minutes to normal time format. i.e.

function clockalize($in){

    $h = intval($in);
    $m = round((((($in - $h) / 100.0) * 60.0) * 100), 0);
    if ($m == 60)
    {
        $h++;
        $m = 0;
    }
    $retval = sprintf("%02d:%02d", $h, $m);
    return $retval;
}


clockalize("17.5"); // 17:30

answered Oct 28 '16 at 09:06

Patrick Jaja

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what about inverse 17:30 -> 17.5 – saber tabatabaee yazdi May 20 '19 at 18:51

score 0 · Answer 4 · answered Dec 14 '16 at 09:02

0

This is a great way and avoids problems with floating point precision:

function convertTime($h) {
    return [floor($h), (floor($h * 60) % 60), floor($h * 3600) % 60];
}

answered Dec 14 '16 at 09:02

Teldan

1

score 0 · Answer 5 · answered Feb 01 '12 at 20:25

0

I am not sure if this is the best way to do this, but

$variabletocutcomputation = 60 * ($dec - $hour);
$min = round($variabletocutcomputation);
$sec = round((60*($variabletocutcomputation - $min)));

answered Feb 01 '12 at 20:25

Justin Pihony

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How to convert a decimal into time, eg. HH:MM:SS

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