Cholesky Decomposition Calculator

Cholesky Decomposition Calculator

Factor a symmetric positive definite matrix into L and L^T, and see the determinant that follows from the diagonal of L.

Last updated: 2026-06-21T07:59:21.695Z

Enter valid numeric entries. The matrix must be square, symmetric, and positive definite.

Decomposition
A = L L^T
det(A) = 51
det(L)7.141428
det(A)51
Lower triangular matrix L
200
120
0.50.751.785357

What is Cholesky decomposition?

Cholesky decomposition writes a symmetric positive definite matrix A as A = L L^T, where L is lower triangular. It is efficient for solving linear systems and computing determinants.

Formula and algorithm

A = L L^T

For each diagonal entry, compute the square root of the adjusted diagonal sum.

For each lower entry, divide the adjusted row sum by the matching diagonal of L.

Worked example

Decompose A = [[4, 2], [2, 3]]

L[1,1] = sqrt(4) = 2

L[2,1] = 2 / 2 = 1

L[2,2] = sqrt(3 - 1^2) = sqrt(2) ≈ 1.414214

det(A) = (2 × 1.414214)^2 = 8

Frequently asked questions

Why must the matrix be symmetric?

Because A = L L^T is always symmetric.

Why must it be positive definite?

The algorithm takes square roots of adjusted diagonal values, which must stay positive.

What does the determinant equal?

For Cholesky, det(A) equals the square of the product of the diagonal entries of L.

Can I use this for non-square matrices?

No. Cholesky decomposition is only defined for square matrices.

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