It is always helpful to tell us what you have (in this case, the starting
row for you data and the regular spaced interval) so we can give you an
exact formula for it. Since you didn't tell us, here is an example which you
can modify for your situation. Let's say your data is in Column C and starts
on Row 4; let's also say the rows you want to sum up are spaced 3 rows apart
(that is, the rows you want to add up are C4, C7, C10, C13, etc.); then
assuming your data does not extend beyond Row 500, this formula will sum up
those rows in Column C...

=SUMPRODUCT((MOD(ROW(C4:C500)-ROW(C4),3)=0)*C4:C500)

A general format for this formula would be...

=SUMPRODUCT((MOD(ROW(<StartRow:<EndRow)-Row(<StartRow),<Interval)=0)*<StartRow:<EndRow )

--
Rick (MVP - Excel)


"Picman" wrote in message
...
Yes they are at regularly spaced intervals.

"John C" wrote:

Are the cells at regularly spaced intervals?
If not, do the cells have some unique identifier in the same row that
they
are in?

If not, remember, there are 30 arguments in each sum, you could nest your
sum statements:
=SUM(SUM(A1,B4,C5,...),SUM(J13,K27,M612))
--
** John C **
Please remember if your question is answered, to mark it answered :). It
helps everyone.


"Picman" wrote:

I have a column with hundreds of populated cells, and I would like to
add up
the sum of more than 30 of these cells. The problem is that they are
not
adjacent to each other and the Excel SUM function seems to limit the
number
of arguments to 30. Is there a way around this?