Ren

I think the problem you are having is because SUMPRODUCT() does not work
with an entire column. Try
=SUMPRODUCT (B1:B65535,C1:C65535)
or adjust to maximum number of rows you need.

Dave

"Ren" wrote in message
...
Hi,

I a few sets of data that would have varying rows, and I need to get the
summation of products of cullumn B*C. How should I do this in excel? using
sumproduct(B:B,C:C) gives me a num error. I want to be able to have this
dynamically updated, hence, I don't want to do this in a macro(unless a
macro
can be automatically executed).

Thanks