How Our Calculators Are Built and Verified

This page explains, honestly and specifically, how The Everything Calculator's formulas are researched, how calculators are tested, how sources are cited, and what to do if something looks wrong. It's here so you can judge the site's reliability for yourself, not just take our word for it.

Formula and Source Research

Each calculator's formula is researched against real external sources — government agencies, standards bodies, professional and academic organizations, and other authoritative references appropriate to its topic. Where a calculator cites a source, that source is linked directly on the page so you can check it yourself. Some calculators have not yet had every detail individually cross-checked against an outside source; ongoing review work is tracked internally, and any confirmed issue gets fixed and, where relevant, noted on the page.

Automated Testing

The site uses automated testing to verify calculator behavior, including expected outputs, boundary conditions, invalid inputs, and regression behavior where applicable. This catches many classes of bugs before they reach a live page, though no amount of testing can guarantee perfection — see the corrections section below for how to report something that still looks wrong.

Estimates, Not Professional Advice

Most calculators on this site produce an estimate based on the numbers you enter and the assumptions built into their formula. A smaller number — exact arithmetic, unit conversions, calendar-date lookups, and true random-number or dice generators — produce an exact or genuinely non-deterministic result instead of an estimate. Either way, none of this is a substitute for advice from a qualified professional who knows your specific situation. Finance, health, safety, and tax calculators carry a disclaimer to that effect; see this site's Privacy Policy and Terms for the full legal detail.

Corrections and Feedback

Formula corrections, source corrections, bug reports, and suggestions for new or improved calculators are always welcome. Visit the Contact page to share what you found — every report gets a real look, though response times can vary.

Who Maintains This Site

The Everything Calculator is built and maintained by one person. See the About page for more.