here is my function:

=sumproduct((C:C="Epoxy") * (D:D="Straight") * (E:E))

as you've already guessed, I get #Value!. I don't know up front how many
rows to include, so I included the entire column. What can I do to my
formula to ignore blanks?

Or do I need to set up some sort of dynamic list?

Thanks,
Steve