Calculate business days

Question

Hi,

I need a method for adding "business days" in PHP. For example, Friday 12/5 + 3 business days = Wednesday 12/10.

At a minimum I need the code to understand weekends, but ideally it should account for US federal holidays as well. I'm sure I could come up with a solution by brute force if necessary, but I'm hoping there's a more elegant approach out there. Anyone?

Thanks.

Answer 1

There are some args for the date() function that should help. If you check date("w") it will give you a number for the day of the week, from 0 for Sunday through 6 for Saturday. So.. maybe something like..

$busDays = 3;
$day = date("w");
if( $day > 2 && $day <= 5 ) { /* if between Wed and Fri */
  $day += 2; /* add 2 more days for weekend */
}
$day += $busDays;

This is just a rough example of one possibility..

Answer 2

For holidays, make an array of days in some format that date() can produce. Example:

// I know, these aren't holidays
$holidays = array(
    'Jan 2',
    'Feb 3',
    'Mar 5',
    'Apr 7',
    // ...
);

Then use the in_array() and date() functions to check if the timestamp represents a holiday:

$day_of_year = date('M j', $timestamp);
$is_holiday = in_array($day_of_year, $holidays);

Answer 3

Here's a function from the user comments on the date() function page in the PHP manual. It's an improvement of an earlier function in the comments that adds support for leap years.

Enter the starting and ending dates, along with an array of any holidays that might be in between, and it returns the working days as an integer:

<?php
//The function returns the no. of business days between two dates and it skips the holidays
function getWorkingDays($startDate,$endDate,$holidays){
    //The total number of days between the two dates. We compute the no. of seconds and divide it to 60*60*24
    //We add one to inlude both dates in the interval.
    $days = (strtotime($endDate) - strtotime($startDate)) / 86400 + 1;

    $no_full_weeks = floor($days / 7);
    $no_remaining_days = fmod($days, 7);

    //It will return 1 if it's Monday,.. ,7 for Sunday
    $the_first_day_of_week = date("N",strtotime($startDate));
    $the_last_day_of_week = date("N",strtotime($endDate));

    //---->The two can be equal in leap years when february has 29 days, the equal sign is added here
    //In the first case the whole interval is within a week, in the second case the interval falls in two weeks.
    if ($the_first_day_of_week <= $the_last_day_of_week){
        if ($the_first_day_of_week <= 6 && 6 <= $the_last_day_of_week) $no_remaining_days--;
        if ($the_first_day_of_week <= 7 && 7 <= $the_last_day_of_week) $no_remaining_days--;
    }
    else{
        if ($the_first_day_of_week <= 6) {
        //In the case when the interval falls in two weeks, there will be a weekend for sure
            $no_remaining_days = $no_remaining_days - 2;
        }
    }

    //The no. of business days is: (number of weeks between the two dates) * (5 working days) + the remainder
//---->february in none leap years gave a remainder of 0 but still calculated weekends between first and last day, this is one way to fix it
   $workingDays = $no_full_weeks * 5;
    if ($no_remaining_days > 0 )
    {
      $workingDays += $no_remaining_days;
    }

    //We subtract the holidays
    foreach($holidays as $holiday){
        $time_stamp=strtotime($holiday);
        //If the holiday doesn't fall in weekend
        if (strtotime($startDate) <= $time_stamp && $time_stamp <= strtotime($endDate) && date("N",$time_stamp) != 6 && date("N",$time_stamp) != 7)
            $workingDays--;
    }

    return $workingDays;
}

//Example:

$holidays=array("2008-12-25","2008-12-26","2009-01-01");

echo getWorkingDays("2008-12-22","2009-01-02",$holidays)
// => will return 7
?>

Answer 4

Here is a function for adding buisness days to a date

 function add_business_days($startdate,$buisnessdays,$holidays,$dateformat){
  $i=1;
  $dayx = strtotime($startdate);
  while($i < $buisnessdays){
   $day = date('N',$dayx);
   $date = date('Y-m-d',$dayx);
   if($day < 6 && !in_array($date,$holidays))$i++;
   $dayx = strtotime($date.' +1 day');
  }
  return date($dateformat,$dayx);
 }

 //Example
 date_default_timezone_set('Europe\London');
 $startdate = '2012-01-08';
 $holidays=array("2012-01-10");
 echo '<p>Start date: '.date('r',strtotime( $startdate));
 echo '<p>'.add_business_days($startdate,7,$holidays,'r');

Another post mentions getWorkingDays (from php.net comments and included here) but I think it breaks if you start on a Sunday and finish on a work day.

Using the following (you'll need to include the getWorkingDays function from previous post)

 date_default_timezone_set('Europe\London');
 //Example:
 $holidays = array('2012-01-10');
 $startDate = '2012-01-08';
 $endDate = '2012-01-13';
 echo getWorkingDays( $startDate,$endDate,$holidays);

Gives the result as 5 not 4

Sun, 08 Jan 2012 00:00:00 +0000 weekend
Mon, 09 Jan 2012 00:00:00 +0000
Tue, 10 Jan 2012 00:00:00 +0000 holiday
Wed, 11 Jan 2012 00:00:00 +0000
Thu, 12 Jan 2012 00:00:00 +0000
Fri, 13 Jan 2012 00:00:00 +0000

The following function was used to generate the above.

     function get_working_days($startDate,$endDate,$holidays){
      $debug = true;
      $work = 0;
      $nowork = 0;
      $dayx = strtotime($startDate);
      $endx = strtotime($endDate);
      if($debug){
       echo '<h1>get_working_days</h1>';
       echo 'startDate: '.date('r',strtotime( $startDate)).'<br>';
       echo 'endDate: '.date('r',strtotime( $endDate)).'<br>';
       var_dump($holidays);
       echo '<p>Go to work...';
      }
      while($dayx <= $endx){
       $day = date('N',$dayx);
       $date = date('Y-m-d',$dayx);
       if($debug)echo '<br />'.date('r',$dayx).' ';
       if($day > 5 || in_array($date,$holidays)){
        $nowork++;
     if($debug){
      if($day > 5)echo 'weekend';
      else echo 'holiday';
     }
       } else $work++;
       $dayx = strtotime($date.' +1 day');
      }
      if($debug){
      echo '<p>No work: '.$nowork.'<br>';
      echo 'Work: '.$work.'<br>';
      echo 'Work + no work: '.($nowork+$work).'<br>';
      echo 'All seconds / seconds in a day: '.floatval(strtotime($endDate)-strtotime($startDate))/floatval(24*60*60);
      }
      return $work;
     }

    date_default_timezone_set('Europe\London');
     //Example:
     $holidays=array("2012-01-10");
     $startDate = '2012-01-08';
     $endDate = '2012-01-13';
//broken
     echo getWorkingDays( $startDate,$endDate,$holidays);
//works
     echo get_working_days( $startDate,$endDate,$holidays);

Bring on the holidays...

Answer 5

neat function..flaminglogos!

thanks! :)

Answer 6

function get_business_days_forward_from_date($num_days, $start_date='', $rtn_fmt='Y-m-d') {

// $start_date will default to today    

if ($start_date=='') { $start_date = date("Y-m-d"); }

$business_day_ct = 0;

$max_days = 10000 + $num_days;  // to avoid any possibility of an infinite loop


// define holidays, this currently only goes to 2012 because, well, you know... ;-)
// if the world is still here after that, you can find more at
// http://www.opm.gov/Operating_Status_Schedules/fedhol/2013.asp
// always add holidays in order, because the iteration will stop when the holiday is > date being tested

$fed_holidays=array(
    "2010-01-01",
    "2010-01-18",
    "2010-02-15",
    "2010-05-31",
    "2010-07-05",
    "2010-09-06",
    "2010-10-11",
    "2010-11-11",
    "2010-11-25",
    "2010-12-24",

    "2010-12-31",
    "2011-01-17",
    "2011-02-21",
    "2011-05-30",
    "2011-07-04",
    "2011-09-05",
    "2011-10-10",
    "2011-11-11",
    "2011-11-24",
    "2011-12-26",

    "2012-01-02",
    "2012-01-16",
    "2012-02-20",
    "2012-05-28",
    "2012-07-04",
    "2012-09-03",
    "2012-10-08",
    "2012-11-12",
    "2012-11-22",
    "2012-12-25",
    );

$curr_date_ymd = date('Y-m-d', strtotime($start_date));    

for ($x=1;$x<$max_days;$x++)
{
    if (intval($num_days)==intval($business_day_ct)) { return(date($rtn_fmt, strtotime($curr_date_ymd))); }  // date found - return

    // get next day to check

    $curr_date_ymd = date('Y-m-d', (strtotime($start_date)+($x * 86400)));   // add 1 day to the current date

    $is_business_day = 1;

    // check if this is a weekend   1 (for Monday) through 7 (for Sunday)

    if ( intval(date("N",strtotime($curr_date_ymd))) > 5) { $is_business_day = 0; }

    //check for holiday
    foreach($fed_holidays as $holiday)
    {
        if (strtotime($holiday)==strtotime($curr_date_ymd))  // holiday found
        {
            $is_business_day = 0;
            break 1;
        }

        if (strtotime($holiday)>strtotime($curr_date_ymd)) { break 1; }  // past date, stop searching (always add holidays in order)


    }

    $business_day_ct = $business_day_ct + $is_business_day;  // increment if this is a business day

} 

// if we get here, you are hosed
return ("ERROR");

}

Answer 7

A function to add or subtract business days from a given date, this doesn't account for holidays.

function dateFromBusinessDays($days, $dateTime=null) {
  $dateTime = is_null($dateTime) ? time() : $dateTime;
  $_day = 0;
  $_direction = $days == 0 ? 0 : intval($days/abs($days));
  $_day_value = (60 * 60 * 24);

  while($_day !== $days) {
    $dateTime += $_direction * $_day_value;

    $_day_w = date("w", $dateTime);
    if ($_day_w > 0 && $_day_w < 6) {
      $_day += $_direction * 1; 
    }
  }

  return $dateTime;
}

use like so...

echo date("m/d/Y", dateFromBusinessDays(-7));
echo date("m/d/Y", dateFromBusinessDays(3, time() + 3*60*60*24));

Answer 8

I had this same need i started with bobbin's first example and ended up with this

  function add_business_days($startdate,$buisnessdays,$holidays=array(),$dateformat){
    $enddate = strtotime($startdate);
    $day = date('N',$enddate);
    while($buisnessdays > 1){
        $enddate = strtotime(date('Y-m-d',$enddate).' +1 day');
        $day = date('N',$enddate);
        if($day < 6 && !in_array($enddate,$holidays))$buisnessdays--;
    }
    return date($dateformat,$enddate);
  }

hth someone

Answer 9

Hello.

The getWorkingDaysBetweenDates function works wrong to august 2010, returns 23 working days (there are 22).

grettings. Eugene

Answer 10

Today is (ORDER DATE): " . '' . date('l, F j, Y', $today) . "

";

//The numerical representation for day of week (Ex. 01 for Monday .... 07 for Sunday $today_numerical = date("N",$today);

//leadtime_days holds the numeric value for the number of business days $leadtime_days = $_POST["leadtime"];

//leadtime is the adjusted date for shipdate $shipdate = time();

while ($leadtime_days > 0) { if ($today_numerical != 5 && $today_numerical != 6) { $shipdate = $shipdate + (60*60*24); $today_numerical = date("N",$shipdate); $leadtime_days --; } else $shipdate = $shipdate + (60*60*24); $today_numerical = date("N",$shipdate); }

echo 'Estimated Ship date: ' . '' . date('l, F j, Y', $shipdate) . ""; ?>