Math & Trig

MMULT Function in Excel

Returns the matrix product of two arrays.

Syntax

  • =MMULT(array1, array2)

Arguments

  • array1 (required): First array
  • array2 (required): Second array

Examples

  • =MMULT(A1:B2, D1:E2) - Multiply 2x2 matrices - Result: 2x2 result

MMULT in reporting workflows

  • Use absolute references when copying formulas across rows.
  • For conditional totals see [SUMIF](/functions/sumif/) and [SUMIFS](/functions/sumifs/).
  • Filtered lists may need [SUBTOTAL](/functions/subtotal/) instead of SUM on visible cells only.

Common errors

  • #VALUE! if dimensions incompatible

Use cases

  • Linear algebra
  • Engineering
  • Data transformation

Frequently asked questions

  • What is MMULT used for in Excel? MMULT performs matrix multiplication - essential for linear algebra, solving systems of equations, transformations in graphics/engineering, and advanced data analysis. It multiplies rows of first matrix by columns of second matrix.
  • What are the dimension requirements for MMULT? Array1 columns must equal Array2 rows. A 3×2 matrix times a 2×4 matrix gives a 3×4 result. If dimensions don't match, you get #VALUE! error. Remember: (m×n) × (n×p) = (m×p).
  • How do I enter MMULT as an array formula? In Excel 365/2021, just type =MMULT(A1:B2,D1:E2) and it spills automatically. In older Excel, select the output range first, type the formula, then press Ctrl+Shift+Enter to enter as array formula.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.