Formula that's automatic adding date when specific workbook is modified

Hi Niclas,

This question seems easy at first glance!
But it really cannot be achieved in native Excel, it needs VBA power!

I've updated your workbook with a fairly good solution achieved by VBA which is the Excel scripting language.

The solution is this code:

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
 Target.Range("C4") = Now()
End Sub

Which is saved in ThisWorkbook code scope.

With this code, each time you save the workbook (which is means that you've made changes to it) this code will trigger and fill the cell C4 with the today's date and time.

Please find the attached file.

Hope that helps