You can use a VBA UDF (user defined function):

Function IsFormula(cell_ref As Range)
IsFormula = cell_ref.HasFormula
End Function

Then you'd use it just like any other worksheet function:

=IsFormula(A1)

This will return either TRUE or FALSE.

You could also use this function to conditionally format the cells.

To use this:

Open the VBE editor: ALT F11
Open the Project Explorer: CTRL R
Locate your file name in the project explorer pane on the left.
Right click the file name
Select: InsertModule
Copy the code above and paste into the window on the right
Return back to Excel: ALT Q

Set the conditional formatting...
Select the cell(s) in question. Assume this is cell A1.
Goto FormatConditional Formatting
Formula Is: =IsFormula(A1)
Click the Format button
Select the desired style(s)
OK out


--
Biff
Microsoft Excel MVP


"todd" wrote in message
...
I'm stumped, I thought there used to be a =isformula to test whether a
cell
is a formula or not.

How can I test for that to see if a formula got overwritten which I do
want
it to do if a user chooses.