Place this code in a Standard Module
Public Function CountDown()
Dim Later As Date
Application.Volatile
Later = CDate("07/11/2018 00:00:01")
CountDown = Format(Later - Now, "d:h:mm:ss")
End Function
To use it, in any Cell use the formula
To be able to change the count down to date, place this Function in a standard Module
Option Explicit
Public Function CountDown(ToTime As Variant)
Dim Later As Date
Application.Volatile
Later = CDate(ToTime)
CountDown = FormatLater - Now, "d:h:mm:ss")
End Function
You can use two cell formulas with it
=CountDown("07/11/2018 00:00:01")
Or
=CountDown(A1) 'Where the new date/time is in Cell A1