How would I track a rolling set of 30 cells?

[Guest]

I am trying to have a cell show me a sum for the past 30 days, updated daily.
The group of the 30 cells I'm summing will need to adjust down one cell
daily.

 

[JE McGimpsey]

One way:

Assume headings in row 1, then data in rows 2:xx, one row per day, date
in column A, numeric data in column B:

=SUM(OFFSET(B2,MAX(0, COUNTA(B:B)-31), 0, 30,1))

 

[MartinW]

Hi CJ

Another way assuming your data is in A1 to A30
then in B30

=IF(A30="","",SUM(A1:A30))
and drag it down as far as you need. The cell references
will update as you drag drown.
i.e. B31 will show =IF(A31="","",SUM(A2:A31)) etc.

The B column will stay blank until you put a value into A

HTH
Martin

 

[Guest]

=SUMPRODUCT(--(A2:A100>=TODAY()-30),B2:B100)