SUMPRODUCT in Microsoft ExcelMultiplies corresponding components in the given arrays, and returns the sum of those products.Syntax SUMPRODUCT(array1,array2,array3, ...) Array1, array2, array3, ... are 2 to 30 arrays whose components you want to multiply and then add. Remarks The array arguments must have the same dimensions. If they do not, SUMPRODUCT returns the #VALUE! error value. SUMPRODUCT treats array entries that are not numeric as if they were zeros. Example Our training video example of sumproduct in Excel demonstrates the calculation of total inventory. Remark The preceding example returns the same result as the formula SUM(A2:B4*C2:D4) entered as an array. Using arrays provides a more general solution for doing operations similar to SUMPRODUCT. For example, you can calculate the sum of the squares of the elements in A2:B4 by using the formula =SUM(A2:B4^2) and pressing CTRL+SHIFT+ENTER simultaneously from the keyboard. 

Further reading on Sumproduct function in Excel 