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.

Answer 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;
}

Answer 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 );