"carl" wrote in message
...
I use this formula:

=COUNTIF(I5:I40;TRUE)/COUNTA(I5:I40)

I would like to change the formula so that it will use the value in cell
A1
(eg 200) like this:

=COUNTIF(I5:I200;TRUE)/COUNTA(I5:I200)

Thank you in advance.

Try this formula:

=COUNTIF(OFFSET(I5;;;A1-4),TRUE)/COUNTA(OFFSET(I5;;;A1-4))

Hope this helps / Lars-Åke