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Condition Number Calculator

κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁ for a small real square matrix. Same engine as Linear System. Singular matrices return infinite. Not a 2-norm product. Runs locally.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary Engine tested · Specification checked · 44/44 tests · Production surface contract 3/3 · v1.10.0
Input interpretation
Enter values to calculate.
Result
—
Model
κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁ for a small real square matrix (order 2–4).
Scope
Real square matrices
Verification
Engine tested · 44/44 tests · Production surface contract 3/3 · Specification checked · v1.10.0
Named expert review
Optional · Not performed
Specification basis
  • ISO 80000-2:2019 Quantities and units — Mathematics
Specification basis
Evidence
23 golden · 2 boundary · 19 property · Production surface contract 3/3 · Artifact integrity PASS
Production
Embedded snapshot: STALE · Last attested schema matched 1.10.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status STALE (1 capability; 163 remain CURRENT) @ 2026-09-19T00:00:17.039Z
Semantic contract
PASS

Formulas

Core equations used by this calculator.

1-norm conditionκ₁(A) = ‖A‖₁ ‖A⁻¹‖₁
Singulardet(A) = 0 ⇒ κ₁ = ∞
iSquare matrices only, order ≤ 4. Reuses the 1-norm already used as a trust field. Ill-conditioned warning when κ₁ ≥ 10⁸. Not a CAS. Not 2-norm / Frobenius κ. Float64.

How to use

1

Enter a square matrix

2×2 or 3×3. Larger composition lives at /workspace/matrix. Inverse and rank are sibling discovery URLs.

2

Read κ₁

Finite when A is invertible. Singular matrices return infinite, not SINGULAR_MATRIX.

Example calculations

Common configurations with formula and result.

ϟ

Diagonal

diag(2, 1)

‖A‖₁=2, ‖A⁻¹‖₁=1
κ₁=2
ϟ

Singular

[[1,2],[2,4]]

det=0
∞

Condition Number calculator specification

Version 1.10.0 · Engine tested

Calculation status

Review policy · Evidence

Definition
κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁. This page is mode=condition on math.linear_algebra. The same κ₁ already appears as a trust field on other modes. Not a second engine. Not κ₂ = σ_max/σ_min as a product.
What it calculates
κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁ for a small real square matrix (order 2–4).
Inputs
  • order
  • a11…
Outputs
  • condition_number
  • infinite
  • status
  • det
Formula
κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁
Assumptions
  • Real square matrices
  • Order ≤ 4
  • Float64
  • Not a CAS
  • Not 2-norm κ₂ / Jordan form
Units
  • dimensionless
Boundary conditions
  • singular A → condition_number null, infinite true
  • unknown mode (including jordan-form) → INVALID_MODE
Example
diag(2,1) → κ₁=2
Validation cases

2 published on this page · 44/44 tests · Production surface contract 3/3 · View evidence

  • order=2 a11=2 a12=0 a21=0 a22=1 → condition_number=2
  • mode=jordan-form order=2 a11=1 a12=0 a21=0 a22=1 → INVALID_MODE
Specification basis
  • ISO 80000-2:2019 Quantities and units — Mathematics
Calculation version
1.10.0

Other calculators in this family: Column Space Calculator, Least Squares Calculator, Left Nullspace Calculator, Linear Equation Calculator, Linear System Calculator, LU Factorization Calculator, Matrix Determinant Calculator, Matrix Eigenvalues Calculator . Explore all Algebra & Equations.

→ Column Space Calculator Column space (image) of a small real square matrix from RREF pivot columns. Same engine as Linear System. Trivial image is {0}. Left-nullspace is a sibling. Runs locally. › → Least Squares Calculator Linear least squares for a small real square system. Full rank uses QR; rank-deficient uses SVD. Same engine as Linear System. Not Statistics regression. Runs locally. › → Left Nullspace Calculator Left-nullspace (cokernel) of a small real square matrix as ker(Aᵀ). Same engine as Linear System. Trivial left kernel is {0}. Not Jordan form. Runs locally. › → Linear Equation Calculator Solve ax + b = rhs for x. Identity and inconsistent cases when a = 0. Not the quadratic formula. Runs locally. › → Linear System Calculator Solve small linear systems Ax = b, plus det, inverse, rank, LU, QR, SVD, least squares, RREF, condition number, nullspace, column space, rowspace, left-nullspace, and eigenvalues. Same engine as the matrix workspace. Not a CAS. Runs locally. › → LU Factorization Calculator Doolittle LU factorization with partial pivoting for a small real matrix. Same engine as Linear System. Not a CAS. Runs locally. › → Matrix Determinant Calculator Determinant of a small real matrix. Same engine as Linear System and the matrix workspace. Not a CAS. Runs locally. › → Matrix Eigenvalues Calculator Eigenvalues and eigenvectors of a small real matrix via the characteristic polynomial. Same engine as Linear System. Not a CAS. Runs locally. ›
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Frequently asked questions

Key distinctions behind the calculation.

Is this a second linear-algebra engine?

No. It is mode=condition on math.linear_algebra, the same engine as /calc/math/linear-system and /workspace/matrix. κ₁ already exists as a trust field on other modes.

Is this the 2-norm condition number σ_max/σ_min?

No. This page reports the 1-norm κ₁. SVD lives at /calc/math/matrix-svd. A κ₂ product stays later on this same engine.