I am running a vlookup, my look up value is a number that is derived from the output of a formula. In the function arguments window, check the lookup_value and table_array values text values are wrapped with quote marks; How To Use Vlookup And Choose To Create A Left Lookup Formula In Excel Excel Microsoft Excel Formulas Vlookup Excel This happens because the syntax of the vlookup function requires that you supply the entire table array as well as a certain number. Vlookup not working showing formula . Show formulas disabled (normal mode) show formulas enabled. @elva_tanguerre first of all, you can get rid of the brackets surrounding ak3. The number one most common reason why a vlookup does not work is because the numbers in your cells are actually text. Real number have no quote marks; Vlookup does not work when based on formula. Error in your vlookup formula, you can quickly find a solution by checking the above causes. As a result, the formula cannot find the l...