I think I missed a set of brackets. Try the following instead...

=SUMPRODUCT((THREED(Data1:Data2!$A$4:$A$291)=Summa ry!$B$1)*(THREED(Data1:
Data2!$H$4:$H$291)=Summary!$A33),(THREED(Data1:Dat a2!I$4:I$291)))

Does this help?

In article ,
"BSantos" wrote:

DOMENIC, I'm getting a #ref error with this formula.
=SUMPRODUCT((THREED(Data1:Data2!$A$4:$A$291)=Summa ry!$B$1)*(THREED(
Data1:Data2!$H$4:$H$291)=Summary!$A33),THREED(Data 1:Data2!I$4:I$291))

can you help? B.