Re: Rolling Calculations

Motaad <Mot...@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote...
I have a spread sheet with three years of monthly data. I need to
calculate for a rolling twelve month total each month.
sum data in columns for (Jan2006 - Dec2006),
sum data in columns for (Feb2006. - Jan2007),
sum data in columns for (Mar2006. - Feb2007, etc.)

How are the months identified? Is the data grouped by year in fixed
size chunks, e.g., each month's data spans 20 rows? Is there another
column with dates?

If column A contained dates and column B the data you want to sum,
both spanned rows 1 to 10000, and if Jan2006 thru Dec2006 were the
first 12 month period to sum, then try the following.


Fill D1 down into D2:D36. Another alternative, shorter, more efficient
but also more complex, would be


which you'd also fill down into D2:D36.