Matrix Addition Calculator

Published on: September 7 2025

This Matrix Addition Calculator helps you add two matrices and shows each step clearly. It works by adding the corresponding entries from matrices of the same dimensions to form a new matrix. This makes it useful for checking answers, understanding how matrix addition works, and practising linear algebra step by step.

Step-by-step method

  1. Check that both matrices have the same number of rows and columns.
  2. Add entries in the same position, such as row 1 column 1 with row 1 column 1.
  3. Write each sum in the matching position of the result matrix.

Formula:

If A = [aij] and B = [bij], then A + B = [aij + bij].

Example 1: Take the matrices below.

12
-3
40
7
+
5
18
-9
2

Step 1 - Check that both matrices have the same number of rows and columns.

In this problem: Matrix A and Matrix B are both 2×2, so they can be added.

12
-3
40
7
+
5
18
-9
2

Step 2 - Add entries in the same position, such as row 1 column 1 with row 1 column 1.

In this problem: Each entry is paired with the entry in the same row and column.

12 + 5
-3 + 18
40 + -9
7 + 2

Step 3 - Write each sum in the matching position of the result matrix.

In this problem: Each sum is placed back into the same position in the answer matrix.

12 + 5 = 17
-3 + 18 = 15
40 + -9 = 31
7 + 2 = 9
=
17
15
31
9

Final answer:

17
15
31
9

Example 2: Take the matrices below.

1000
-2
33
4
15
6
7
8
9
+
1
2
30
4
5
6
-7
0
11

Step 1 - Check that both matrices have the same number of rows and columns.

In this problem: Matrix A and Matrix B are both 3×3, so they can be added.

1000
-2
33
4
15
6
7
8
9
+
1
2
30
4
5
6
-7
0
11

Step 2 - Add entries in the same position, such as row 1 column 1 with row 1 column 1.

In this problem: Each entry is paired with the entry in the same row and column.

1000 + 1
-2 + 2
33 + 30
4 + 4
15 + 5
6 + 6
7 + -7
8 + 0
9 + 11

Step 3 - Write each sum in the matching position of the result matrix.

In this problem: Each sum is placed back into the same position in the answer matrix.

1000 + 1 = 1001
-2 + 2 = 0
33 + 30 = 63
4 + 4 = 8
15 + 5 = 20
6 + 6 = 12
7 + -7 = 0
8 + 0 = 8
9 + 11 = 20
=
1001
0
63
8
20
12
0
8
20

Final answer:

1001
0
63
8
20
12
0
8
20
Matrix A
+
Matrix B