NETWORKDAYSMISC

Returns the number of days between two dates using a defined list of workdays.
For instructions on how to add a function to a workbook refer to the page under Inserting Functions

Option Base 1    

'lStartDate - The starting date
'lEndDate - The finishing date
'rgeHolidays - The dates to exclude from the working calendar, holidays and floating days.
'rgeWorkdays - The days of the week that you want to include.

Public Function NETWORKDAYSMISC(ByVal lStartDate As Long, _ 
                                ByVal lEndDate As Long, _ 
                                ByVal rgeHolidays As Range, _ 
                                ByVal rgeWorkDays As Range) As Long 
 
Dim iweekdaycount As Integer 
Dim bhasvalidworkday As Boolean 
Dim bisvalidworkday As Boolean 
Dim lnewdate As Long 
Dim arholidays() As Long 
Dim iholidaycount As Integer 
Dim iarrayno As Integer 
Dim ldaycount As Long 

   If lStartDate = lEndDate Then NETWORKDAYSMISC = 0 
   If lStartDate = lEndDate Then Exit Function 

   bhasvalidworkday = False 
   For iweekdaycount = 1 To 7 Step 1 
      If rgeWorkDays.Item(iweekdaycount).Text <> "" Then 
         bhasvalidworkday = True 
         Exit For 
      End If 
   Next iweekdaycount 

   If bhasvalidworkday = False Then Call MsgBox("The rgeWorkDays parameter is incorrect") 
   If bhasvalidworkday = False Then Exit Function 

   ReDim arholidays(rgeHolidays.Count) 
   For iholidaycount = 1 To rgeHolidays.Count 
      If rgeHolidays.Item(iholidaycount).Value <> "" Then 
         arholidays(iholidaycount) = rgeHolidays.Item(iholidaycount).Value 
      Else 
         Exit For 
      End If 
   Next iholidaycount 
   ReDim Preserve arholidays(iholidaycount - 1) 

   lnewdate = lStartDate 
   ldaycount = 0 

   Do Until lnewdate = lEndDate 
      bisvalidworkday = True 

      If lStartDate < lEndDate Then lnewdate = lnewdate + 1 
      If lStartDate > lEndDate Then lnewdate = lnewdate - 1 

      If rgeWorkDays.Item(VBA.Weekday(lnewdate)).Text <> "" Then 
         For iarrayno = 1 To UBound(arholidays) 
            If lnewdate = arholidays(iarrayno) Then 
                bisvalidworkday = False 
                Exit For 
            End If 
         Next iarrayno 

         If bisvalidworkday = True Then 
            If (lStartDate - lEndDate) < 0 Then ldaycount = ldaycount + 1 
            If (lStartDate - lEndDate) > 0 Then ldaycount = ldaycount - 1 
         End If 
      End If 
   Loop 
   NETWORKDAYSMISC = ldaycount 
End Function 

Test