Calculating working hours between two dates

Question

I need a PHP method for calculating working hours between two dates based on a 8 hour working day and excluding weekends and bank holidays.

For example the difference between 2012-01-01T08:30:00 AND 2012-01-05T10:30:00 in working hours is actually 26 working hours because the first two days are weekend/bank holiday which just leaves 3 working days and the time differnce of 2 hours i.e. 3*8+2=26.

I have used @flamingLogos excellent answer to a previous question but cannot get it to take into account the time as well as date.

Solution 1

Function below calculates working hours between two dates, provided in text format such as '2013-11-27 13:40', taking work day hours from 9 to 17 (can be changed).

function get_working_hours($from,$to)
{
    // timestamps
    $from_timestamp = strtotime($from);
    $to_timestamp = strtotime($to);

    // work day seconds
    $workday_start_hour = 9;
    $workday_end_hour = 17;
    $workday_seconds = ($workday_end_hour - $workday_start_hour)*3600;

    // work days beetwen dates, minus 1 day
    $from_date = date('Y-m-d',$from_timestamp);
    $to_date = date('Y-m-d',$to_timestamp);
    $workdays_number = count(get_workdays($from_date,$to_date))-1;
    $workdays_number = $workdays_number<0 ? 0 : $workdays_number;

    // start and end time
    $start_time_in_seconds = date("H",$from_timestamp)*3600+date("i",$from_timestamp)*60;
    $end_time_in_seconds = date("H",$to_timestamp)*3600+date("i",$to_timestamp)*60;

    // final calculations
    $working_hours = ($workdays_number * $workday_seconds + $end_time_in_seconds - $start_time_in_seconds) / 86400 * 24;

    return $working_hours;
}

There are two additional functions. One returns work days array...

function get_workdays($from,$to) 
{
    // arrays
    $days_array = array();
    $skipdays = array("Saturday", "Sunday");
    $skipdates = get_holidays();

    // other variables
    $i = 0;
    $current = $from;

    if($current == $to) // same dates
    {
        $timestamp = strtotime($from);
        if (!in_array(date("l", $timestamp), $skipdays)&&!in_array(date("Y-m-d", $timestamp), $skipdates)) {
            $days_array[] = date("Y-m-d",$timestamp);
        }
    }
    elseif($current < $to) // different dates
    {
        while ($current < $to) {
            $timestamp = strtotime($from." +".$i." day");
            if (!in_array(date("l", $timestamp), $skipdays)&&!in_array(date("Y-m-d", $timestamp), $skipdates)) {
                $days_array[] = date("Y-m-d",$timestamp);
            }
            $current = date("Y-m-d",$timestamp);
            $i++;
        }
    }

    return $days_array;
}

and second - returns holidays array

function get_holidays() 
{
    // arrays
    $days_array = array();

    // You have to put there your source of holidays and make them as array...
    // For example, database in Codeigniter:
    // $days_array = $this->my_model->get_holidays_array();

    return $days_array;
}

Solution 2

Maybe you can use this function :

function work_hours_diff($date1,$date2) {
    if ($date1>$date2) { $tmp=$date1; $date1=$date2; $date2=$tmp; unset($tmp); $sign=-1; } else $sign = 1;
    if ($date1==$date2) return 0;

    $days = 0;
    $working_days = array(1,2,3,4,5); // Monday-->Friday
    $working_hours = array(8.5, 17.5); // from 8:30(am) to 17:30
    $current_date = $date1;
    $beg_h = floor($working_hours[0]); $beg_m = ($working_hours[0]*60)%60;
    $end_h = floor($working_hours[1]); $end_m = ($working_hours[1]*60)%60;

    // setup the very next first working timestamp

    if (!in_array(date('w',$current_date) , $working_days)) {
        // the current day is not a working day

        // the current timestamp is set at the begining of the working day
        $current_date = mktime( $beg_h, $beg_m, 0, date('n',$current_date), date('j',$current_date), date('Y',$current_date) );
        // search for the next working day
        while ( !in_array(date('w',$current_date) , $working_days) ) {
            $current_date += 24*3600; // next day
        }
    } else {
        // check if the current timestamp is inside working hours

        $date0 = mktime( $beg_h, $beg_m, 0, date('n',$current_date), date('j',$current_date), date('Y',$current_date) );
        // it's before working hours, let's update it
        if ($current_date<$date0) $current_date = $date0;

        $date3 = mktime( $end_h, $end_m, 59, date('n',$current_date), date('j',$current_date), date('Y',$current_date) );
        if ($date3<$current_date) {
            // outch ! it's after working hours, let's find the next working day
            $current_date += 24*3600; // the day after
            // and set timestamp as the begining of the working day
            $current_date = mktime( $beg_h, $beg_m, 0, date('n',$current_date), date('j',$current_date), date('Y',$current_date) );
            while ( !in_array(date('w',$current_date) , $working_days) ) {
                $current_date += 24*3600; // next day
            }
        }
    }

    // so, $current_date is now the first working timestamp available...

    // calculate the number of seconds from current timestamp to the end of the working day
    $date0 = mktime( $end_h, $end_m, 59, date('n',$current_date), date('j',$current_date), date('Y',$current_date) );
    $seconds = $date0-$current_date+1;

    printf("\nFrom %s To %s : %d hours\n",date('d/m/y H:i',$date1),date('d/m/y H:i',$date0),$seconds/3600);

    // calculate the number of days from the current day to the end day

    $date3 = mktime( $beg_h, $beg_m, 0, date('n',$date2), date('j',$date2), date('Y',$date2) );
    while ( $current_date < $date3 ) {
        $current_date += 24*3600; // next day
        if (in_array(date('w',$current_date) , $working_days) ) $days++; // it's a working day
    }
    if ($days>0) $days--; //because we've allready count the first day (in $seconds)

    printf("\nFrom %s To %s : %d working days\n",date('d/m/y H:i',$date1),date('d/m/y H:i',$date3),$days);

    // check if end's timestamp is inside working hours
    $date0 = mktime( $beg_h, 0, 0, date('n',$date2), date('j',$date2), date('Y',$date2) );
    if ($date2<$date0) {
        // it's before, so nothing more !
    } else {
        // is it after ?
        $date3 = mktime( $end_h, $end_m, 59, date('n',$date2), date('j',$date2), date('Y',$date2) );
        if ($date2>$date3) $date2=$date3;
        // calculate the number of seconds from current timestamp to the final timestamp
        $tmp = $date2-$date0+1;
        $seconds += $tmp;
        printf("\nFrom %s To %s : %d hours\n",date('d/m/y H:i',$date2),date('d/m/y H:i',$date3),$tmp/3600);
    }

    // calculate the working days in seconds

    $seconds += 3600*($working_hours[1]-$working_hours[0])*$days;

    printf("\nFrom %s To %s : %d hours\n",date('d/m/y H:i',$date1),date('d/m/y H:i',$date2),$seconds/3600);

    return $sign * $seconds/3600; // to get hours
}

I put printf() to show what it is done (you can remove them)

You call it like that :

date_default_timezone_set("America/Los_Angeles");
$dt2 = strtotime("2012-01-01 05:25:00");
$dt1 = strtotime("2012-01-19 12:40:00");
echo work_hours_diff($dt1 , $dt2 );

Solution 3

The other two proposals don't work if you choose start or end in a non-working day or time. This are the results my code gets using a working day of 9:00 to 20:00 and rest days Saturday and Sunday.

get_working_hours('2016-10-08 08:00:00', '2016-10-08 21:00:00'); //Saturday: 0 hrs
get_working_hours('2016-10-10 08:00:00', '2016-10-10 21:00:00'); //Monday: 11 hrs
get_working_hours('2016-10-10 10:00:00', '2016-10-10 19:00:00'); //Monday: 9 hrs
get_working_hours('2016-10-07 19:00:00', '2016-10-10 10:00:00'); //fri-mon: 2 hrs
get_working_hours('2016-10-08 19:00:00', '2016-10-10 10:00:00'); //sat-mon: 1 hrs
get_working_hours('2016-10-07 19:00:00', '2016-10-09 10:00:00'); //fri-sun: 1 hrs

function get_working_hours($ini_str,$end_str){
    //config
    $ini_time = [9,0]; //hr, min
    $end_time = [20,0]; //hr, min
    //date objects
    $ini = date_create($ini_str);
    $ini_wk = date_time_set(date_create($ini_str),$ini_time[0],$ini_time[1]);
    $end = date_create($end_str);
    $end_wk = date_time_set(date_create($end_str),$end_time[0],$end_time[1]);
    //days
    $workdays_arr = get_workdays($ini,$end);
    $workdays_count = count($workdays_arr);
    $workday_seconds = (($end_time[0] * 60 + $end_time[1]) - ($ini_time[0] * 60 + $ini_time[1])) * 60;
    //get time difference
    $ini_seconds = 0;
    $end_seconds = 0;
    if(in_array($ini->format('Y-m-d'),$workdays_arr)) $ini_seconds = $ini->format('U') - $ini_wk->format('U');
    if(in_array($end->format('Y-m-d'),$workdays_arr)) $end_seconds = $end_wk->format('U') - $end->format('U');
    $seconds_dif = $ini_seconds > 0 ? $ini_seconds : 0;
    if($end_seconds > 0) $seconds_dif += $end_seconds;
    //final calculations
    $working_seconds = ($workdays_count * $workday_seconds) - $seconds_dif;
    echo $ini_str.' - '.$end_str.'; Working Hours:'.($working_seconds / 3600).b();
    return $working_seconds / 3600; //return hrs
}

function get_workdays($ini,$end){
    //config
    $skipdays = [6,0]; //saturday:6; sunday:0
    $skipdates = []; //eg: ['2016-10-10'];
    //vars
    $current = clone $ini;
    $current_disp = $current->format('Y-m-d');
    $end_disp = $end->format('Y-m-d');
    $days_arr = [];
    //days range
    while($current_disp <= $end_disp){
        if(!in_array($current->format('w'),$skipdays) && !in_array($current_disp,$skipdates)){
            $days_arr[] = $current_disp;
        }
        $current->add(new DateInterval('P1D')); //adds one day
        $current_disp = $current->format('Y-m-d');
    }
    return $days_arr;
}

Comments

[Roy]

Excellent excellent code, hajlabajla ! One wonders though, if there is an elegant way to use half day (0900-1300) for saturdays

[zeroweb]

I do not think this works. $start = '2019-09-03 12:00'; $end = '2019-09-03 20:00'; $a = $support->getWorkingHours($start, $end ); $workday_start_hour = 0; $workday_end_hour = 17; I am expecting 5 hours however I am getting 8 hours