G'day John

You could use the Worksheet_Change event.

Something like

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Range("YourRange")) Is Nothing Then
Application.Run "YourMacro"
End If
End Sub

("YourRange") can be multiple Cells ("A1" , "K20", Z1:Z100)

HTH
Mark.