What do you do in Jan, Feb and Mar when there aren't 3 preceding months?

--
Biff
Microsoft Excel MVP


"Kylie" wrote in message
...
Hi
Am wanting to determine a 3 month average based on the 3 months proceeding
the current month.

The spreadsheet contains 12 months of data. If the current month is
determined elsewhere in the data on the spreadsheet, how can I use that so
that I can determine the 3 month average for the months preceeding the
current month.
Eg

Current month = May

jan feb mar apr may june july aug sep oct nov dec last
3
month avg
5 7 10 6 9
??

(based on feb mar apr)

When June comes around the 3 month average should then move to be based on
Mar, Apr & May.

Any thoughts??