Hi,

What do I need to add to the below formula, to get the return result as
"zero", when one of the cell in column AO is not "Y". Prensently, the return
result is #DIV/0!.

=SUMPRODUCT(--('ES 0421'!$AC$2:$AC$1903=$B13),--('ES
0421'!$AO$2:$AO$1903="Y"),('ES 0421'!$AI$2:$AI$1903)/A2)

Thanks,
Priscilla