Dim oldVal
Private Sub Worksheet_Change(ByVal Target As Range)
On Error GoTo ws_exit:
Application.EnableEvents = False
If Not Intersect(Target, Me.Range("A1")) Is Nothing Then
With Target
.Value = .Value + oldVal
oldVal = .Value
End With
End If
ws_exit:
Application.EnableEvents = True
End Sub
'This is worksheet event code, which means that it needs to be
'placed in the appropriate worksheet code module, not a standard
'code module. To do this, right-click on the sheet tab, select
'the View Code option from the menu, and paste the code in.
--
HTH
Bob Phillips
... looking out across Poole Harbour to the Purbecks
(remove nothere from the email address if mailing direct)