# Excel MMULT Function

Summary

The Excel MMULT function returns the matrix product of two arrays. The array result contains the same number of rows as array1 and the same number of columns as array2. If returning multiple results in an array on the worksheet, enter as an array formula with control + shift + enter.

Purpose

Perform matrix multiplication

Return value

The matrix product of two arrays

Syntax

=MMULT (array1, array2)

Arguments

**array1**- The first array to multiply.**array2**- The second array to multiply.

Usage notes

The MMULT function returns the matrix product of two arrays. The column count of **array1** must equal the row count of **array** 2. The array result will contain the same number of rows as **array1** and the same number of columns as **array2**. For example, you can multiply a 4 x 2 array by a 2 x 2 array to return a 4 x 2 array result.

If returning multiple results in an array on the worksheet, enter as a multi-cell array formula with control + shift + enter.

Notes:

- Arrays must contain only numbers.
- Columns in
**array1**must equal the rows in**array2**. **Array1**and**Array2**can be provided as cell ranges, array constants, or references.- Formulas that return arrays must be entered as array formulas using control + shift + enter.
- MMULT returns the #VALUE! error if any cells in
**array1**and**array2**are not numbers, or if**array1**columns do not equal**array2**rows.