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 differenc

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;
}