Hi
Thanks for looking

Below is the formula i'm using and it works just fine.
=SUMPRODUCT(--(YEAR(Serial!$G$2:$G$3222)=$B$1),--(MONTH(Serial!$G$2:$G$3222)=D2)

What i'm trying to do is select the whole column (G) as below
=SUMPRODUCT(--(YEAR(Serial!G:G)=$B$1),--(MONTH(Serial!G:G)=D2)

I just can't get this to work, any ideas

Cheers
Peter (UK)