Hi Gary,
Thanks for the swift reply.

"Worksheet code area" presumably the code bit attached to Sheet1 (where the
data is?
Also, don't I have to refer to the cell that I need to know has changed (A126?

Cheers
Colin

"Gary''s Student" wrote:

First make sure that Sub UpdatePrices() is in a standard module. Then insert
the following event macro in the worksheet code area:

Private Sub Worksheet_Calculate()
Call UpdatePrices
End Sub