=SUMPRODUCT(--(NOT(ISNUMBER(MATCH(Sheet1!$G$9:$G$152,E10:E12,0)) )),Sheet1!$H$9:$H$152)+SUMPRODUCT(--(NOT(ISNUMBER(MATCH(Sheet2!$G$9:$G$152,E10:E12,0)) )),Sheet2!$H$9:$H$152)

BTW, your formula can be simplified

=SUMIF(Sheet1!$G$9:$G$152,E10,Sheet1!$H$9:$H$152)+ SUMIF(Sheet2!$G$9:$G$29,E10,Sheet2!$H$9:$H$29)

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HTH

Bob

(there's no email, no snail mail, but somewhere should be gmail in my addy)



"Taxed Mind" wrote in message
...
Hi

I have this equation which works well to SUM the values in two sheets if
the
tax rate applied in the same row is the same as that in this sheet's cell
E10.

=SUM(SUMIF('Sheet1'!$G$9:$G$152,"="&E10,'Sheet1'!$ H$9:$H$152))+(SUMIF('Sheet2'!$G$9:$G$29,"="&E10,'S heet2'!$H$9:$H$29))

I have a similar equation to calculate a further two values (in cells E11
and E12), as I currently have three different tax rates.

However, if purchases are made overseas using tax rates that I cannot
forsee
I need another equation to calculate the values in the two sheets if the
tax
rate applied in the same row is NOT the same as that in this sheet's cell
E10, E11 or E12.

Anybody any thoughts on how to approach this?

Thanks in advance, a Taxed Mind.