You could using a worksheet_change() event like so (This works in column A).
To implement go to http://www.nickhodge.co.uk/vba/vbaim....htm#EventCode

Private Sub Worksheet_Change(ByVal Target As Range)
With Application
If Not .Intersect(Target, Columns("A:A")) Is Nothing Then
..EnableEvents = False
Target.Value = Target.Value * 1.1
..EnableEvents = True
End If
End With
End Sub

--
HTH
Nick Hodge
Microsoft MVP - Excel
Southampton, England
HIS


"cjrolls" wrote in message
...
Hello Is there any way to have excel 2000 automatically enter the new
amount
in same cell of what i type plus GST of 10 %. e.g I type 10.46 in to cell
and
when I push enter excel replaces it with 11.506
Many thanks