Perhaps C4 or A1 contain numbers, but in the ranges some of the
numbers are actually text values (or vice versa). Or perhaps you have
text and some of the values in the ranges have extra spaces (which you
can't see, so it looks like they should match).

Hope this helps.

Pete

On Nov 11, 11:36*am, Sarah (OGI)
wrote:
I've got 2 worksheets in 1 workbook, one labelled PO and one labelled OCR..

In the PO worksheet, I've entered the following formula:
=SUMPRODUCT(--(OCR!A2:A65536=C4),--(OCR!D2:D65536=A1),--(OCR!V2:V65536))

It's only returning a value of £15,674, but it should be returning a value
of £251,537 (when checking the data manually).

I must be missing something with my formula - is there an obvious error?

Thanks