If you want to average for data in col d and dates in col a then try this
array formula which must be entered using ctrl+shift+enter vs just enter.

=AVERAGE(IF(MONTH(ChecksA)=2,ChecksD))

--
Don Guillett
SalesAid Software

"gevans" wrote in message
...
I need formula that will determine a rolling 12 month average. I'm
starting
with individual days, so I need something that will recognise the start
and
end of each month, something that is date based rather than just count
based.
Any ideas?
Thanks in advance!
--
gevans