How a calculator page is made
- Formula first. We use standard, published methods: the annuity formula used in U.S. loan disclosures, CDC body-mass-index categories, the Mifflin-St Jeor energy equation and similar. Where several methods exist we say which one we use and why.
- Tested against published numbers. Each formula has at least five automated tests, including at least two worked examples published by an outside authority (for example a CFPB sample Loan Estimate or the U.S. Army body-fat worksheet). Pages are not published until all tests pass.
- Sources on the page. The “Formula and sources” section links to the documents we relied on.
- Plain-English explanations. Text is written for this site. We do not copy wording, tables or examples from other calculator sites.
- Health pages describe population estimates for adults and always carry a medical disclaimer. We do not publish dosing or pregnancy calculators.
Corrections
If you find a mistake, use the contact page. We confirm the issue, fix the formula or text, add a test for the case, and update the “last checked” date on the page.
Advertising
Advertising never influences which formula or result we show. Ads are limited to three per page and are kept away from the calculator itself.