Thanks DaddyLL. This does the trick on my simple example. It seems the solution was where I was looking for it but I still can't get my head around the steps in this formula. Any chance you can explain the logic? My next step is to apply this formula to the list @E2:E5 and net the giver/taker values such that A=(50) & B=(101.25) and the net for all = 0. Further, I will actually need to calculate the tax rate in column F from two other columns, say Prior year taxes / Prior year revenue. I think I can handle this if I can just grasp the logic in this sumproduct(sumif) solution you provided.