MMULT function
Returns the matrix product of two arrays. The result is an array with the same number of rows as array1 and the same number of columns as array2.
Syntax
MMULT(array1,array2)
Array1, array2 are the arrays you want to multiply.
Remarks

The number of columns in array1 must be the same as the number of rows in array2, and both arrays must contain only numbers.

Array1 and array2 can be given as cell ranges, array constants, or references.

MMULT returns the #VALUE! error when:

Any cells are empty or contain text.

The number of columns in array1 is different from the number of rows in array2.


The matrix product array a of two arrays b and c is:
where i is the row number, and j is the column number.

Formulas that return arrays must be entered as array formulas.
Example 1
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

Press CTRL+C.

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.


Note The formula in the example must be entered as an array formula. After copying the example to a blank worksheet, select the range A8:B9 starting with the formula cell. Press F2, and then press CTRL+SHIFT+ENTER. If the formula is not entered as an array formula, the single result is 2.
Example 2
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

Press CTRL+C.

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.


Note The formula in the example must be entered as an array formula. After copying the example to a blank worksheet, select the range A8:B9 starting with the formula cell. Press F2, and then press CTRL+SHIFT+ENTER. If the formula is not entered as an array formula, the single result is 6.