While there are thousands of articles you can find via Google, here's a few
to get you pointed in right direction:

Basic info:
http://www.meadinkent.co.uk/xlsumproduct.htm
Comparison to DSUM and SUMIF:
http://www.ozgrid.com/Excel/sum-if.htm
Use of double negative:
http://www.mcgimpsey.com/excel/formulae/doubleneg.html

And of course, the hundreds of examples within this forum!

--
Best Regards,

Luke M
*Remember to click "yes" if this post helped you!*


"Brad Autry" wrote:

Hello,

After reviewing these boards here the past few days, I'm finding the
SUMPRODUCT function coming up often for things I'd not previously considered.
I tried to find a comprehensive source of info on its uses and syntax, but
I've only been able to find bits and pieces or examples of it being used with
no real explanation.

Does anyone know of a good website that offers a thorough explanation of the
sumproduct function? Thanks in advance.

Brad