Hmm,

What's a 'trailing' day? I think your saying you want to sum the last 30
entries of data. This sums the last 30 entries in column A and is dynamic so
as new entries are added it stills sums the last 30

=SUM(OFFSET(A1,COUNTA(A:A)-30,):OFFSET(A1,COUNTA(A:A),))
--
Mike

When competing hypotheses are otherwise equal, adopt the hypothesis that
introduces the fewest assumptions while still sufficiently answering the
question.


"ctante" wrote:

I am trying to build a rolling spreadsheet based on days. I want to have a
total for the trailing 30 days, but keep all the information that is older
than 30 days. If I lock the formula, and add new days it keeps the original
30 day calculation, instead of adding on 1 new day and dropping off the
oldest day of the 30.