Thanks, Mike!

Using your idea, it appears that the culprit was actually column A - a
column of 4-digit values, but a mixture of numbers and text. I've changed
these to integers and it works fine now!!

Many thanks!

"Mike H" wrote:

Sarah,

There's nothing wrong with the formula so it must be data problems. Put this
in w2
and drag down and it should evaluate as TRUE for your numbers. If it
evaluates as false then there not numbers

=isnumber(V2)

Mike

"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