[RESOLVED] Calculating the number of hours & minutes between 2 dates on the same day...

Smurlos

Hi All

I'm having a bit of an issue calculating the number of hours between two times.

Basically, I am calculating a team rota creation program in PHP to allow managers to create a team schedule online. There's then a read only page for the staff to log in and see their hours.

When creating the rota, the manager selects a slot and a window appears. You select the department they will work in and then enter a start time in the "field_start" input box and finish time in the "field_finish" input box in HH:MM format.

During the week shift patterns are generally 10:00 - 17:00, 17:00 - 00:00, 18:00 - 00:00 or 12:00 - 20:00.

Then friday/sat/sun, you get some 14:00 - 22:00, but the finish time is 01:00 (i.e. the next day). But if you're on a day shift, the start is generally 09:45 - 17:00.

So based on having for example a start time of "16:00" and end time of "01:00" how would i go about calculating the number of hours (which should be 9)? And then the same for an 09:45 - 17:00 start, this should say 7:15 (or 7.25 would be better as this is the format i need it in ultimately).

I've had a look around and all i can see are ones where you enter in the full date string...

Thanks for your time
Carl

Smurlos

function calculatetime($start,$finish) {

$start_time = $_POST[form_start];
$finish_time = $_POST[form_finish];

$start_hour = substr($start_time,0,2);
$start_min = substr($start_time,3,2);

$finish_hour = substr($finish_time,0,2);
$finish_min = substr($finish_time,3,2);

if ($finish_time > $start_time) {

$hours = $finish_hour - $start_hour;
$mins = $finish_min - $start_min;

}
else if ($start_time == "00:00" && $finish_time == "00:00") {
$hours = "00";
$mins = "00";
}
else {

$endhour = $finish_hour + 24;
$hours = $endhour - $start_hour;
$mins = $finish_min - $start_min;

}

$the_mins = $mins / 60;

$the_time = "$hours.$the_mins";

return $the_time;

}

I tried the above, but based on a test of "20:45" to "22:00" it returned "2.-0.25" which is obviously wrong as it should be "1.25"... :-S

johanafm

Shouldn't it even be 1:15? Or do you want mintes expressed as decimal hours?

$times = array(	array('start' => '9:45', 'end' => '12:00'),		/* 2:15 */
				array('start' => '17:00', 'end' => '22:00'),	/* 5:00 */
				array('start' => '22:00', 'end' => '05:00')		/* 7:00 */
		);


foreach($times as $t)
{
	$s_parts = explode(':', $t['start']);
	$e_parts = explode(':', $t['end']);


$hs = $s_parts[0];	# start hour
$ms = $s_parts[1];	# start minute

$he = $e_parts[0];	# end hour
$me = $e_parts[1];	# end minute

# end hour only < start hour if new day
if ($he < $hs)
	$he += 24;

# end minute < start minute, decrease end hour by one and add 60 minutes
if ($me < $ms)
{
	--$he;
	$me += 60;
}

$hrs = $he - $hs;
if ($hrs < 10)
	$hrs = '0'.$hrs;
$mins = $me - $ms;
if ($mins < 10)
	$mins = '0'.$mins;

echo '<div>'.$hrs.':'.$mins.'</div>';

}

Smurlos

Thanks sooo much Johanafm - bit of modification and it works perfectly :-)

I've made it also convert to decimals so that I can calculate rough costing based on pay rate :-)

Smurlos

function calculatetime($start_time,$finish_time) {


$s_parts = explode(':', $start_time);
$e_parts = explode(':', $finish_time);


$hs = $s_parts[0];    # start hour
$ms = $s_parts[1];    # start minute

$he = $e_parts[0];    # end hour
$me = $e_parts[1];    # end minute

# end hour only < start hour if new day
if ($he < $hs)
    $he += 24;

# end minute < start minute, decrease end hour by one and add 60 minutes
if ($me < $ms)
{
    --$he;
    $me += 60;
}

$hrs = $he - $hs;
if ($hrs < 10)
    $hrs = '0'.$hrs;
$mins = $me - $ms;
if ($mins < 10)
    $mins = '0'.$mins;

$the_time = "$hrs:$mins";

return $the_time;


}

This calculates the time.

function calculate_cost($time,$payrate) {

$hour = substr($time,0,2);
$min = substr($time,3,2);

$deci_min = $min / 60;

$deci_time = $hour + $deci_min;

$cost = round($deci_time * $payrate, 2);

return $cost;

}

And this calculates the costing.

Thanks for your help!