woops, that sent before I had a chance to finish....

So, I've tried =STDEV(CO12:INDEX(CO:CO,ROW()-1)) but that will want to
calculate the whole column. I need it to be from CO12:"infinity"

also, because of how the worksheet is built, I can't easily move this
formula out of the CO column.

Thanks!

"John" wrote:

Hi everyone, I hope some can help me with this:

I need to run a standard deviation on a range within a column that start at
CO12 and goes on to dynamically added rows

So far I've tried:

=STDEV(CO12:INDEX(CO:CO,ROW()-1))