The Last Business Day

When developing a worksheet, you may have a need to know the last business day of a given month. Assuming that your business days run Monday through Friday, the following formula will return the desired date:

=DATE(YEAR(A1),MONTH(A1)+1,0)-(MAX(0,WEEKDAY
(DATE(YEAR(A1),MONTH(A1)+1,0),2)-5))

This formula returns a date that is only a Monday through Friday, and always the last such day in the month represented by the date in A1. For some purposes, you may need to know what the last Friday of any given month is. This is easily determined with this formula:

=DATE(YEAR(A1),MONTH(A1)+1,0)-WEEKDAY(DATE
(YEAR(A1),MONTH(A1)+1,0))+(WEEKDAY(DATE
(YEAR(A1),MONTH(A1)+1,0))>5)*7-1

This formula calculates the last day of the month for the date in cell A1 and, based on what day of the week that date is, subtracts the appropriate number of days to return the previous Friday.

If you want to take business holidays into account, then the complexity of the formula gets quite high, quite quickly. Because of that, it is best to create a user-defined function (a macro) that will determine the last business day and compensate for holidays.

The following macro returns a date, Monday through Friday, that represents the last business day. The date is compared against a holiday list (HolidayList), which should be a named range in your workbook. If the date is found to be a holiday, then the ending business day is decremented until a suitable day is located.

Function LastWorkDay(lRawDate As Long, _
    Optional rHolidayList As Range, _
    Optional bFriday As Boolean = False) As Long

    LastWorkDay = DateSerial(Year(lRawDate), _
      Month(lRawDate) + 1, 0) - 0
    If bFriday Then
        LastWorkDay = MakeItFriday(LastWorkDay)
    Else
        LastWorkDay = NoWeekends(LastWorkDay)
    End If

    If Not rHolidayList Is Nothing Then
        Do Until myMatch(LastWorkDay, rHolidayList) = 0
            LastWorkDay = LastWorkDay - 1
            If bFriday Then
                LastWorkDay = MakeItFriday(LastWorkDay)
            Else
                LastWorkDay = NoWeekends(LastWorkDay)
            End If
        Loop
    End If
End Function

Private Function myMatch(vValue, rng As Range) As Long
    myMatch = 0
    On Error Resume Next
    myMatch = Application.WorksheetFunction _
        .Match(vValue, rng, 0)
    On Error GoTo 0
End Function

Private Function NoWeekends(lLastDay As Long) As Long
    NoWeekends = lLastDay
    If Weekday(lLastDay) = vbSunday Then _
      NoWeekends = NoWeekends - 2
    If Weekday(lLastDay) = vbSaturday Then _
      NoWeekends = NoWeekends - 1
End Function

Private Function MakeItFriday(lLastDay As Long) As Long
    MakeItFriday = lLastDay
    While Weekday(MakeItFriday) <> vbFriday
        MakeItFriday = MakeItFriday - 1
    Wend
End Function

Notice that there are three private functions that are included. These functions are called from within the main LastWorkDay function. The first one, myMatch, is a "wrapper" for the regular Match method. This usage is included because of the required error handling.

The second function, NoWeekdends, is used to back a date up to the previous Friday if it just happens to be a Saturday or Sunday. The MakeItFriday function is used to ensure that a date will always be a Friday.

To use this user-defined function from your worksheet, you use it in a formula, like this:

=LastWorkDay(A1, HolidayList, TRUE)

The first parameter (A1) is the date to be evaluated. The second parameter (HolidayList) is an optional list of holiday dates. As shown here, it is assumed that HolidayList is a named range in the worksheet. If this parameter is provided, then the function makes sure that any date it returns is not on the list of dates in HolidayList.

The final parameter is also optional; it can be either TRUE or FALSE. (The default, if it is not specified, is FALSE.) If this parameter is set to TRUE, then the function always returns the last Friday of the month. If this parameter is TRUE and the HolidayList is provided, then the function returns the last non-holiday Friday of the month.