Quick answer

Choose a size, enter each entry of A, and read the adjoint grid labeled with c_ij style results.

Formula

  • adj(A) = transpose of cofactor matrix
  • Supports 2×2, 3×3, and 4×4 on this site
  • Runs locally in your browser

Introduction

A dedicated calculator saves time when minors stack up or you want a fast homework check. The Adjoint Matrix Calculator lives on the home page at the calculator anchor and applies cofactors, then transpose, internally.

For manual steps first, see how to find the adjoint matrix. You should still write cofactor steps at least once per size so exam questions feel familiar.

When you need many worked cases to compare against your entries, open adjoint matrix examples and enter the same matrices in the tool afterward.

What the calculator does

It accepts numeric entries, including fractions like 3/4, and applies the classical adjugate definition: cofactors, then transpose.

Results appear in a grid aligned with standard matrix indexing so you can compare c_11, c_12, and so on with your paper work.

Nothing in the calculation needs a server round trip for the math itself, which keeps practice sessions private on your device.

Browser tools are useful while you learn: you can test many matrices in a row and watch how a single sign change alters the entire adjoint grid.

The tool presents adj(A) directly. Build cofactors on paper if your assignment requires the intermediate cofactor matrix C before the transpose.

Matching textbook output

  • Input: square matrix A
  • Internal: minors → cofactors → transpose
  • Output: adj(A) with same dimensions as A

If your instructor uses the word adjugate, the output here is the same object under that name.

When your hand computation disagrees with the tool, re-check minors before you blame the transpose. One wrong deletion poisons the whole grid.

Use det(A) from your course methods separately if you need an inverse; divide adj(A) by det(A) only when det(A) ≠ 0.

Change one entry in a 3×3 matrix and watch how multiple adjoint entries shift because minors overlap.

Using the tool

  1. Pick matrix size. Select 2×2, 3×3, or 4×4 to match the problem statement.
  2. Enter every cell. Fill all coefficients. Empty cells block the result until the matrix is complete.
  3. Read adj(A). Compare each output entry with your cofactor table. Labels follow row-column order.
  4. Clear and retry. Use reset to try a new matrix without reloading the page.
  5. Cross-check one row. Compute one row of cofactors by hand, then trust the tool for the remaining rows when time is short.

Calculator workflow

Enter A = [[1, 2, 0], [0, 1, 1], [2, 0, 1]] for a 3×3 exercise. The tool returns the adjoint grid you would obtain after nine cofactors and a transpose.

Change one entry, such as flipping the sign of a_23, and watch how multiple adjoint entries shift because minors overlap.

At 4×4, sixteen cofactors each involve 3×3 determinants. The calculator is especially helpful at that size even when you understand the theory.

Follow your instructor policy on showing steps. Many courses want cofactor work on paper even if a tool confirms the final grid.