Hello,

I need help with a rolling/trailing 30 day formula in excel. I have my dates on one column and revenue in the next column. I used the formula below,

=SUM(OFFSET(B3,COUNTA(B:B)-30,):OFFSET(B3,COUNTA(B:B),))

and after the first 30 days were calculated, the following cells had zeroes and I have more than 90 days of data. I need to be able to add data from one day, subtract revenue from the first day of the month and have this updated with each new day.

Thanks.
Amy.