Editorial and calculation policy

How we check calculators

Formula and example checks

Every calculator engine must name at least one source and include at least one independently sourced worked example. The full test suite recomputes those examples and compares their outputs with the expected values. Shared validation also checks input types, ranges, units, and preset restrictions.

What is listed in search

A calculator is only submitted to search engines once it has a clear address, a name and explanation that describe it accurately, declared inputs and outputs, named sources, at least one independently sourced worked example, and a checked configuration. Anything that does not meet all of those stays reachable by direct link, but is marked noindex and kept out of the sitemap.

Calculations known by several names

A calculation often has more than one common name. Where two names describe the same calculation, one page is the canonical one and the alternatives redirect to it permanently, so the same calculation is never published as several competing pages. Every alternative name still works as a link and still finds the page from the site's own search.

How the text around a calculator is written

The explanation on a page is built from that calculator's own declared inputs, outputs, method, worked examples, warnings and sources. Figures quoted in the text are the figures the calculator produces, rounded the way the page shows them. The surrounding text can never change what a calculator computes, and no factual claim is added that is not carried by a source named on the page.

Every page is read by an automated content audit on each release, which checks that the title, description, headings, answers and sources describe that page and agree with what it calculates.

Sources, limits, and professional decisions

Calculator pages show their sources, assumptions, visible working, and any applicable warning. Health, medical, financial, tax, legal, safety, and engineering results are informational tools; they do not replace a qualified professional. A disclaimer never makes an incorrect formula acceptable.

Live data sources

A few calculators open with a live figure already filled in. Exchange rates are the European Central Bank's daily euro reference rates, refreshed each business day; crypto prices come from CoinGecko, refreshed hourly; US fuel prices are the Energy Information Administration's weekly national averages. Each figure is labelled with its source and time on the page, is indicative only, and can be overwritten with your own number. Rates and prices move; the figure you are quoted by a bank, exchange or station will differ.

Our research crawler

A crawler identifying itself as CalculatorFoxResearchBot occasionally requests public pages while we check how a subject is commonly presented and what readers ask about it. It obeys robots.txt, requests only a small number of pages, reads the title and heading structure, and never stores or republishes the text of another site's page. To refuse it, disallow CalculatorFoxResearchBot in your robots.txt and it will stop.

Corrections

Reported errors should include the calculator name, the unexpected result, and a public source if available—but no private inputs. Confirmed errors are fixed in the engine and protected by a regression test before release. Report a problem to support.