Inverse Matrix Method Calculator

Enter matrices, pick size, and calculate inverses. Get determinants, steps, and solutions in clean tables. Download results, compare examples, and learn faster today now.

Calculator

Enter a square matrix A and an optional vector b. The tool computes A⁻¹ and can solve Ax=b using x=A⁻¹b.

Supported sizes: 2×2 to 6×6.
Adjoint is restricted; larger sizes fall back.
Rounding affects display, not internal steps.
Smaller ε allows tiny pivots; can be risky.
Compute x=A⁻¹b after inversion.
Row steps are truncated for readability.

Matrix A
Tip: You can enter fractions like -3/8.
Vector b
b is used only when “Solve Ax=b” is enabled.
Actions
Reset
After submission, results appear above this form. Use exports to save your calculations.
Quick checks
  • Inverse exists only if det(A) ≠ 0.
  • High cond∞(A) means results may be sensitive.
  • Max |I − A·A⁻¹| should be near zero.

Example data table

Example A and b
A (3×3)
472
361
253
b
1
0
4
Expected outputs (rounded)
A⁻¹ (approx.)
1.4444-1.2222-0.5556
-0.77780.88890.2222
0.3333-0.66670.3333
x = A⁻¹b (approx.)
-0.7778
0.1111
1.6667
Use “Load Example” to populate these values automatically.

Formula used

Inverse matrix method
If A is invertible, the inverse A⁻¹ satisfies A·A⁻¹ = I. The calculator finds A⁻¹ using Gauss–Jordan elimination with partial pivoting.
Solving a linear system
For Ax=b, multiply both sides by A⁻¹: x = A⁻¹b. The tool reports x and basic stability metrics.
Notes: det(A) = 0 means no inverse. High cond∞(A) can amplify rounding errors.

How to use this calculator

  1. Select the matrix size that matches your problem.
  2. Enter values for A; fractions like 5/6 are allowed.
  3. Optionally enter vector b and enable “Solve Ax=b”.
  4. Choose a method and display precision, then press Submit.
  5. Review A⁻¹, diagnostics, and x, then export as CSV or PDF.

Why inverses support reliable solving

An inverse summarizes how a square matrix transforms every vector. If A is invertible, each right‑hand side b yields a unique solution x, and A⁻¹ can be reused for many b values. This calculator focuses on 2×2 through 6×6 problems common in classes and small models. Always review det(A) and stability diagnostics, especially when inputs have very different magnitudes. Use it to explore linear transformations and double‑check worked examples quickly today.

Gauss–Jordan elimination with pivoting

The tool forms [A | I] and applies row operations until the left block becomes I, producing A⁻¹ on the right. Partial pivoting swaps the strongest pivot into place to avoid dividing by tiny values. Work grows roughly as O(n³), so small n remains fast. The pivot tolerance ε marks pivots as effectively zero, and optional steps list the operations performed. Fraction inputs are accepted, then converted to decimals for computation.

Determinant checks and interpretability

det(A) is a quick invertibility test: det(A)=0 means no inverse. The calculator estimates det(A) using elimination with row swaps, matching the pivot strategy used for inversion. For 2×2 and 3×3, an adjoint approach based on cofactors and det(A) is available for learning and manual verification. A determinant near zero often indicates a nearly singular matrix.

Condition number and error diagnostics

Sensitivity is approximated by cond∞(A)=‖A‖∞·‖A⁻¹‖∞. Values close to 1 suggest a well‑conditioned matrix, while large values imply amplified rounding effects. The check max |I − A·A⁻¹| verifies that the computed inverse reproduces the identity matrix. If error is high, rescale inputs, tighten ε carefully, or use simpler fractions. Display precision affects tables only. Aim for errors near 0 within tolerance.

Practical workflow and reporting

Enable Ax=b to compute x=A⁻¹b after inversion and compare solutions across different b vectors. For a single solve, direct elimination is usually preferred, but the inverse method is useful for instruction and repeated solves. CSV exports suit spreadsheets and plotting, while the PDF summary suits assignments and reviews. Keep reports with inputs, rounding, and diagnostics for traceability. Export both formats to keep a clear record.

FAQs

What sizes does the calculator handle?

It supports square matrices from 2×2 up to 6×6. Select a size, and the input grids update for matrix A and vector b.

When does an inverse not exist?

An inverse does not exist when det(A)=0, meaning A is singular. If pivots fall below the tolerance ε, the tool reports the matrix as singular or nearly singular.

Why is Gauss–Jordan used for larger matrices?

Adjoint and cofactor formulas grow expensive and can overflow as size increases. Gauss–Jordan scales more predictably, uses pivoting for better stability, and fits typical 4×4 to 6×6 classroom problems.

What does cond∞(A) tell me?

It estimates how sensitive results are to small input changes. A low value suggests stable inversion, while a high value means rounding or measurement noise can noticeably change A⁻¹ and x.

How should I choose the pivot tolerance ε?

Keep ε small, such as 1e-12 for well-scaled inputs. If your matrix entries are very small or very large, rescale the matrix first; increasing ε too much may incorrectly reject valid pivots.

Do the CSV and PDF exports include everything?

Yes. Exports include your matrix A, vector b, det(A), cond∞(A), the inverse A⁻¹, and the optional solution x. Use them to document inputs, rounding, and computed outputs.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.