Matrix inverse calculator

Type the matrix one row per line to get its inverse A⁻¹, where A × A⁻¹ = I. If the determinant is zero, there is no inverse.

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How to use it

  1. Enter matrix (one row per line).
  2. The result appears straight away and updates as you edit.
  3. Copy the result, or copy a link that keeps the same values to share it.

How it is calculated

A⁻¹ = adj(A) ÷ det(A), where adj(A) is the transpose of the cofactor matrix Cij = (-1)^(i+j) × det(Mij). For 2 × 2: [a b; c d]⁻¹ = [d -b; -c a] ÷ (ad - bc).

Example

Result: Inverse (exact fractions): 3/5 -7/10 -1/5 2/5; Determinant: 10.

4 7
2 6
 3/5  -7/10
-1/5    2/5

Limits and caveats

  • Accepts square matrices from 2 × 2 to 4 × 4.
  • Exact fractions appear only when every entry is a whole number.

Questions about this tool

When does a matrix have an inverse?

When it is square and its determinant is not zero.

How can I check the inverse?

Multiply the matrix by its inverse; you should get the identity matrix I, with 1 on the diagonal and 0 elsewhere.

What is the inverse of [4 7; 2 6]?

The determinant is 4×6 - 7×2 = 10, so the inverse is [6 -7; -2 4] ÷ 10 = [0.6 -0.7; -0.2 0.4].