Auto update a date

maceslin 

Let's say that you want the current date/time in column M whenever a cell in columns A to L is changed by the user.

Right-click the sheet tab.

Select 'View Code' from the context menu.

Copy the following code into the worksheet module:

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim rw As Range
    If Not Intersect(Range("A:L"), Target) Is Nothing Then
        Application.ScreenUpdating = False
        Application.EnableEvents = False
        For Each rw In Intersect(Range("A:L"), Target).Rows
            Range("M" & rw.Row).Value = Now
        Next rw
        Application.EnableEvents = True
        Application.ScreenUpdating = True
    End If
End Sub

Switch back to Excel.

Save the workbook as a macro-enabled workbook (.xlsm).

Make sure that you allow macros when you open the workbook.