Accuracy & Testing Standards

1. Deterministic Calculation Engines

Every calculator on Calcady executes purely client-side within your browser using typed TypeScript and React runtime engines. Calculations are deterministic:

• Reproducible Arithmetic: Given the same set of numerical inputs, the engine produces the exact same output every single time, without random variation or probabilistic drift.
• Zero Black-Box AI at Runtime: Calculations are performed using explicit algebraic equations and lookup tables, never generative AI models or stochastic heuristics.
• Client-Side Execution: Your numbers never travel over the network or touch remote servers. Calculations occur instantly on your device, ensuring privacy and responsiveness.

2. Automated Testing Suite

Calcady maintains an automated test suite executed via Vitest to verify core calculation algorithms and UI components against regressions:

• Automated Test Execution: Over 200 automated unit and regression tests run across our development test suite, covering foundational mathematics, handheld calculator functions, and trade calculation logic.
• Preserving Working Code: In accordance with our development policies, calculation engines are decoupled from page styling and SEO copy. Mathematical routines are preserved during layout or content updates unless a demonstrable formula error is proven against authoritative documentation.
• Continuous Suite Expansion: Automated test coverage is continually expanded as new reference test vectors and standard equations are cataloged across our calculator library.

3. Reference Test Vectors

Calcady uses deterministic calculator engines and automated reference tests where validated test cases are available. Our golden test suite (src/test/golden/) locks core algorithms against published solutions:

Test vectors assert that computed results match published manual calculations within strictly defined numerical tolerances (e.g., ±0.01% or nearest fractional increment).

4. Source Provenance & Standards Registry

When a calculator depends on an external standard, Calcady identifies the relevant reference and edition when that information has been verified. Rather than presenting unattributed numbers, Calcady explicitly documents governing standards, published editions, and primary code sections implemented in our tools.

You can explore our complete directory of referenced codes, editions, and linked tools in our dedicated Standards Registry:

5. Input Validation & Boundary Handling

Calculators implement input clamping, type coercion, and edge-case guardrails to protect against numerical singularities and invalid states:

• Division by Zero: Mathematical denominators are guarded to prevent unchecked Infinity. When a denominator reaches zero, tools display an explicit advisory state or guidance prompt.
• Domain Constraints: Negative roots, logarithmic domain errors, and impossible physical values (such as negative absolute temperatures or negative pipe lengths) are caught before calculation.
• Precision & Formatting: Standard IEEE 754 double-precision floating-point arithmetic is formatted cleanly to domain standards—monetary figures round to two decimals, engineering dimensions round to specified tape-measure increments (e.g., 1/16" or 1/32"), and scientific outputs use standard significant digits.

6. Version Tracking & Change Logging

When mathematical formulas, code standard editions, or algorithm assumptions are updated, changes are recorded in our public Calculator Change Log.

Each entry details the affected tool, the governing standard migration (e.g., updating ampacity tables to a newer code cycle), the rationale for the change, and the specific technical modifications implemented.

8. Limits of Automated Verification

While automated testing ensures that algorithms reliably calculate what they were programmed to compute, computational tools have inherent limitations: