Multiplies corresponding components in the given arrays, and returns the sum of those products.
Array1, array2, array3, ... are 2 to 255 arrays whose components you want to multiply and then add.
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.
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
Create a blank workbook or worksheet.
Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help
In the worksheet, select cell A1, and press CTRL+V.
To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
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.