Linear Algebra Tool

Inverse Matrix Calculator - Matrix Inversion Calculator & Adjugate Matrix Calculator

Free inverse matrix calculator & matrix inverse calculator. Calculate the inverse of 2×2 and 3×3 matrices using the adjugate method. Get step-by-step solutions, verify results, and understand matrix inversion with detailed explanations.

Last updated: October 30, 2025

2×2 and 3×3 matrix inversion
Step-by-step solutions with adjugate method
Automatic verification and determinant check

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Inverse Matrix Calculator
Calculate the inverse of square matrices using the adjugate method. Supports 2×2 and 3×3 matrices.

Inverse Matrix Calculator Features

2×2 Matrix Inverse Calculator
Calculate inverse of 2×2 matrices using direct formula

Formula

A⁻¹ = (1/det) × [[d, -b], [-c, a]]

Fast calculation for 2×2 matrices

3×3 Matrix Inverse Calculator
Calculate inverse using cofactor and adjugate method

Method

A⁻¹ = (1/det) × Adjugate(A)

Full step-by-step process shown

Adjugate Matrix Calculator
Calculate adjugate (adjoint) matrix step-by-step

Definition

Adjugate = (Cofactor)ᵀ

Transpose of cofactor matrix

Determinant Verification
Check if matrix is invertible using determinant

Condition

det(A) ≠ 0

Matrix must have non-zero determinant

Inverse Verification
Verify result by checking A × A⁻¹ = I

Check

A × A⁻¹ = I

Automatic verification included

Step-by-Step Solutions
Detailed explanations for each calculation step

Includes

All intermediate steps

Learn the matrix inversion process

Quick Example Result

2×2 Matrix: A = [[2, 3], [1, 4]]

Determinant

5

Inverse

[[0.8, -0.6], [-0.2, 0.4]]

How the Inverse Matrix Calculator Works

Our inverse matrix calculator uses the adjugate method to find matrix inverses. The process involves calculating the determinant, finding the cofactor matrix, transposing to get the adjugate, and dividing by the determinant. This method works for any invertible square matrix and provides complete step-by-step solutions.

Matrix Inversion Formula

For 2×2: A⁻¹ = (1/det(A)) × [[a₂₂, -a₁₂], [-a₂₁, a₁₁]]
For 3×3 and larger: A⁻¹ = (1/det(A)) × Adjugate(A)
Adjugate: Adjugate(A) = (Cofactor(A))ᵀ
Cofactor: Cᵢⱼ = (-1)ⁱ⁺ʲ × det(Minorᵢⱼ)

The determinant must be non-zero for the matrix to be invertible. If det(A) = 0, the matrix is singular and has no inverse.

Mathematical Foundation

Matrix inversion is a fundamental operation in linear algebra. An invertible matrix (also called non-singular or regular) has a unique inverse that satisfies A × A⁻¹ = A⁻¹ × A = I, where I is the identity matrix. Inverse matrices are essential for solving systems of linear equations, matrix division, and many other applications.

  • A matrix is invertible if and only if its determinant is non-zero
  • The inverse of a 2×2 matrix has a simple direct formula
  • For 3×3 and larger matrices, the adjugate method is most practical
  • Matrix inverses are unique: if A⁻¹ exists, it is the only matrix satisfying A × A⁻¹ = I
  • The inverse of a product: (AB)⁻¹ = B⁻¹A⁻¹ (note the reversed order)
  • Transpose of inverse: (A⁻¹)ᵀ = (Aᵀ)⁻¹

Applications of Inverse Matrices

Inverse matrices have numerous practical applications:

  • Solving Linear Systems: Ax = b → x = A⁻¹b
  • Computer Graphics: Transformations, rotations, scaling inverses
  • Cryptography: Encryption/decryption algorithms
  • Statistics: Covariance matrices, regression analysis
  • Engineering: Circuit analysis, control systems, signal processing
  • Economics: Input-output models, Leontief models

Sources & References

  • Linear Algebra and Its Applications - David C. Lay (5th Edition)Comprehensive textbook on matrix operations and inverses
  • Introduction to Linear Algebra - Gilbert Strang (5th Edition)MIT OpenCourseWare classic on matrix theory
  • Khan Academy - Matrix Inverses and DeterminantsInteractive lessons on matrix inversion and related concepts

Inverse Matrix Calculator Examples

2×2 Matrix Inverse Example
Calculate the inverse of A = [[2, 3], [1, 4]]

Given Matrix:

A = [[2, 3], [1, 4]]
  • Step 1: Calculate determinant
  • det(A) = 2×4 - 3×1 = 8 - 3 = 5
  • Step 2: Apply formula
  • A⁻¹ = (1/5) × [[4, -3], [-1, 2]]

Solution:

Inverse Matrix:

A⁻¹ = [[0.8, -0.6], [-0.2, 0.4]]

Verification: A × A⁻¹ = I ✓

Result: Matrix is invertible with determinant = 5

The inverse exists and can be calculated using the formula above.

3×3 Matrix Example

For 3×3 matrices, use:

1) Find cofactor matrix

2) Transpose to get adjugate

3) Divide by determinant

Singular Matrix

If det(A) = 0:

Matrix is NOT invertible

Rows/columns are linearly dependent

Frequently Asked Questions

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