Say your numbers were in A1 to A100, try this *array* formula:

=AVERAGE(A100:INDEX(A1:A100,LARGE(ROW(1:100)*(A1:A 100<""),20)))

--
Array formulas must be entered with CSE, <Ctrl <Shift <Enter, instead of
the regular <Enter, which will *automatically* enclose the formula in curly
brackets, which *cannot* be done manually. Also, you must use CSE when
revising the formula.

--
HTH,

RD

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"Mike D." wrote in message
...
I am looking for a way to average a series of number in a column. I would
like this formula to average the numbers up to a quantity of 20. So, if
there are 3 numbers in the column, I would like it to average those 3. If
there are 23, I would like it average the last 20. Thanks, Mike.