Sub CalculateDateDifference()
Dim xStartDate As Date
Dim sDate As String
Dim xEndDate As Date, dTestDate As Date
Dim xDay As Long, lCount As Long, i As Long
    On Error Resume Next
    xEndDate = Date
    sDate = InputBox("Enter the start date", "Start Date", "")
    If IsDate(sDate) = False Then
        MsgBox "Please input a valid date.", vbInformation, "Date Calculation"
        Exit Sub
    End If
    xStartDate = CDate(sDate)
    If xStartDate > xEndDate Then
        MsgBox "The start date must be before the end date!", vbInformation, "Date Calculation"
        Exit Sub
    End If
    xDay = DateDiff("d", xStartDate, xEndDate)
    lCount = 0: dTestDate = xStartDate
    For i = 1 To xDay
        If Weekday(dTestDate) > 1 And Weekday(dTestDate) < 7 Then lCount = lCount + 1
        dTestDate = dTestDate + 1
    Next i
    MsgBox "There are " & lCount & " work days from " & xStartDate & " to " & xEndDate & vbCrLf, vbInformation, "Date Calculation"
End Sub