Попробуйте это
Sub DateTest()
'convert the cell to text format and prints the date
Range("C5").NumberFormat = "@"
Range("C5") = Format(#10/18/2018#, "mmm-yy")
'gets the no of days between two dates
MsgBox "No of days : " & DateDiff("d", #1/1/2019#, Date, vbMonday)
'gets the no of working days between two dates
MsgBox "No of working days : " & WorksheetFunction.NetworkDays(#1/1/2019#, Date)
End Sub