How to Multiply Matrices in MATLAB: Syntax and Examples

In MATLAB, you multiply matrices using the * operator between two matrices. Both matrices must have compatible sizes, where the number of columns in the first matrix equals the number of rows in the second matrix.

Syntax

The basic syntax for matrix multiplication in MATLAB is:

C = A * B;

Here, A and B are matrices. The result C is the product matrix. The number of columns in A must match the number of rows in B for multiplication to work.

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C = A * B;

Example

This example shows how to multiply two matrices A and B in MATLAB and display the result.

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A = [1 2 3; 4 5 6];
B = [7 8; 9 10; 11 12];
C = A * B;
disp(C);

Output

  58    64
 139   154

Common Pitfalls

One common mistake is trying to multiply matrices with incompatible sizes. For example, if A is 2x3 and B is 2x2, multiplication A * B will cause an error because the number of columns in A (3) does not equal the number of rows in B (2).

Also, using element-wise multiplication .* instead of matrix multiplication * is a frequent confusion.

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A = [1 2 3; 4 5 6];
B = [7 8; 9 10];
% Wrong: incompatible sizes
% C = A * B; % This will error

% Correct: transpose B or adjust sizes
B_correct = [7 8; 9 10; 11 12];
C = A * B_correct;

Quick Reference

Operation	Syntax	Description
Matrix multiplication	C = A * B	Multiply matrices A and B with compatible sizes
Element-wise multiplication	C = A .* B	Multiply each element of A by corresponding element of B
Matrix size check	size(A,2) == size(B,1)	Check if multiplication is possible

Key Takeaways

Use the * operator to multiply matrices in MATLAB.

Ensure the number of columns in the first matrix equals the number of rows in the second.

Element-wise multiplication uses .* and is different from matrix multiplication.

Check matrix sizes before multiplying to avoid errors.

Use disp() to display the resulting matrix after multiplication.