Calculator Methodology

Last reviewed: July 21, 2026

Formula selection

We prefer formulas published by standards bodies, government agencies, professional organizations, or peer-reviewed research. Each calculator documents assumptions, units, rounding, and important limitations.

Testing

Before publication, formulas are checked with representative examples, boundary values, invalid inputs, and unit conversions. Results are compared with an independent calculation or authoritative example where available.

High-impact topics

Health, finance, tax, legal, credit, and insurance tools are educational estimates. They are not professional advice and require additional review and an effective-date check before publication.

Corrections

If you find an error, please contact us. We investigate reproducible issues and add regression tests for confirmed calculation defects.