Assuming that you currently have 10 sheets named Clin1, Clin2, etc...

=SUMPRODUCT(SUMIF(INDIRECT("'Clin"&ROW(INDIRECT("1 :10"))&"'!K2:K1000"),B8,INDIRECT("'Clin"&ROW(INDIR ECT("1:10"))&"'!U2:U1000")))

OR

=SUMPRODUCT(SUMIF(INDIRECT("'Clin"&ROW(INDIRECT("1 :"&C8))&"'!K2:K1000"),B8,INDIRECT("'Clin"&ROW(INDI RECT("1:"&C8))&"'!U2:U1000")))

...where C8 contains the number of sheets you currently have. So when
you add another sheet, let's say you add sheet Clin11, enter 11 in C8
and that sheet will automatically be taken into account.

Hope this help!

Mike@Q Wrote:
Hi

I am trying to write a SUMIF formula that will sum across a range of
worksheets in a workbook. I never know how many worksheets there will
be in
this range. The formula I am trying is
=SUMIF(Clin1:ClinEND!K:K,NOTES!B8,Clin1:ClinEND!U: U).

Can anyone help? If this is not possible using a SUMIF, is there
another
formula that would work?

Thanks

Mike


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