We are using Excel 2003 but can upgrade if necessary. We need to compute (or lookup) a value based on two inputs. Both inputs will be Excel dropdown boxes. The first one will have values 6 , 9 , 12 , 16 , 20 . The second dropdown has 6x6 , 10x10 , 20x20 . How can we lookup the corresponding value and place the result into a separate cell? Answer It doesn't need to be quite that complex. Take for example the following. Select your column headers and name them Input1. (Range E1:I1 in the example.) Select your row headers and name them Input2. (Range D2:D4) Select your data and name it Data. (Range E2:I4) Use data validation to get the dropdowns. Select cell B2 and click on Data - Data Validation. Set Validation criteria Allow to List and Source to =Input1 Do whatever you want for Input Message and Error Alert. (I turned them off.) Repeat for your 2nd input. (cell B3 gets source =Input2 ) In your Result cell, type in this formula =INDEX(Data,MATCH(B3,Input2,0),MATCH(B2,Input1,0)) ...