Math

3x3 Matrix Determinant Calculator

Determinant of a 3x3 matrix by cofactor expansion.

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ⓘ Live results

Results
Determinant
-3
Singular?
No — matrix is invertible

Quick answer

The determinant is found by expanding along the first row with alternating signs and 2x2 sub-determinants.

det = a(ei-fh) - b(di-fg) + c(dh-eg)

How to use the 3x3 Matrix Determinant Calculator

  1. 1Enter the nine entries of the matrix row by row.
  2. 2Cofactor expansion along the first row is applied automatically.
  3. 3A determinant of zero means the matrix has no inverse.

Worked example

Using the values the calculator loads with:

Inputs

  • a1
  • b2
  • c3
  • d4
  • e5
  • f6
  • g7
  • h8
  • i10

Results

  • Determinant-3
  • Singular?No — matrix is invertible

Frequently asked questions

What does a zero determinant mean?

The matrix is singular — its rows/columns are linearly dependent.

Can I use this for a 2x2 matrix?

Use the dedicated matrix determinant calculator for 2x2 matrices instead.

About this calculator

Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.