rolling 12 month average

[Guest]

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!

 

[Don Guillett]

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))

 

[Peo Sjoblom]

Start of month (with date in A1)

=DATE(YEAR(A1),MONTH(A1),1)

end

=DATE(YEAR(A1),MONTH(A1)+1,0)

12 months ago from end of month subtract 12

=DATE(YEAR(A1),MONTH(A1)-11,0)

=AVERAGE(IF((A2:A1000>=DATE(YEAR(A1),MONTH(A1)-11,0))*(A2:A1000<=DATE(YEAR(A1),MONTH(A1)+1,0)),B2:B1000))


will average values in B2:B1000 where dates in A2:A1000 are greater than 12
months from end of month of date in A1 AND smaller than end of month with
date in A1

A1 can be replaced with TODAY() to use today's date

needs to be entered with ctrl + shift & enter



--

Regards,

Peo Sjoblom

Northwest Excel Solutions

Portland, Oregon

 

[Guest]

Thanks, Peo, that will work just fine!

 

[Guest]

Don, I don't understand the function (ChecksA), and I can't get your formula
to work. I am entering it as written, and using Ctr/Shift/Enter so it will
enter as an array.

 

[Don Guillett]

checksa and b are defined names of ranges. Just substitute your range
addresses instead.