First create a list range from A1 to A15 and call it "MySheets" no quote
A1: Brent
A2: Amber
A3: Lisa
and so on...

=SUMPRODUCT(SUMIF(INDIRECT("'"&MySheets&"'!C9:C27" ),A11,INDIRECT("'"&MySheets&"'!B9:B27")))




"Bongard" wrote:

Hi, I am trying to conditionally sum across multiple tabs. I have a
workbook with about 15 worksheets and I need to sum the amount of
students on each worksheet (cells B9:B27 on every tab) each time for
the respective subject (C:9:C27 on every tab) on my Summary worksheet.
I tried the following formula but am getting a #REF! error

{=SUM(IF(Start:Finish!$C$9:$C$27=A11,Start:Finish! $B$9:$B$27,""))}

This says if C9:C27 = A11 (the subject on my summary worksheet) then
sum B9:B27 and do so on every worksheet from Start:Finish, or at least
thats what I am trying to get it to do. I know this can't be that
difficult but would someone please point me in the right direction?

I would greatly appreciate it!

Thanks in advance,
Brian