Our methodology

1. Formula sourcing

Each calculator begins with a primary source — a textbook, regulatory standard, peer-reviewed paper, or authoritative reference. The source is cited on the calculator page itself.

2. Implementation

The formula is implemented as pure JavaScript so it runs entirely in your browser. No server call. No tracking. The function takes validated numerical inputs and returns structured outputs.

3. Test cases

Every calculator ships with at least three test cases with known expected results. These come from worked examples in textbooks, regulator reference data, or independently verified sources. Tests run on every build; if any fail, the calculator cannot be published.

4. Peer review

Calculators in sensitive domains (health, finance, engineering) are reviewed by a subject-matter expert before publication. The reviewer's name is listed on the page.

5. Display precision

Inputs and outputs are rounded for display only. Internal computations use full floating-point precision. We document decimal precision per output.

6. Limitations

Where a calculator makes simplifying assumptions (ignoring taxes, neglecting friction, assuming steady state), those assumptions are stated in the calculator content. We never pretend a model is more accurate than it is.

7. Updates

When a formula, standard, or guideline changes, the corresponding calculator is updated and the "Last updated" date reflects the revision. Major methodology changes are logged in a changelog.

8. Open verification

Every calculator shows its formula explicitly. You can verify any calculation by running the inputs through the formula manually. No black boxes.