Indsæt følgende kode i et alm. modul:
Public Vent As Double
Sub StartTid()
On Error Resume Next
Vent = Now + TimeSerial(0, 0, 1)
Application.OnTime Vent, "StartTid", , True
Range("A1").Value = Format(Time, "hh:mm:ss")
End Sub
Sub StopTid()
On Error Resume Next
Application.OnTime Vent, "StartTid", , False
End Sub