About and Review Policy

What each calculator page includes

• The formula or method the calculator applies, written out in full.
• A worked example whose result is computed by the same code that runs the calculator.
• Links to the standards bodies, agencies or publications the method comes from.
• The date the page was last reviewed.

How calculators are checked

Every calculator has test cases with answers worked out by hand or taken from the cited source. We run the tests whenever a calculator is added or changed. Unit conversions use the exact legal definitions of the units rather than rounded factors.

Limits of the results

Results are estimates based on the values you enter and on published general-purpose formulas. Health calculators describe population averages and cannot account for your medical history. Finance calculators leave out taxes, fees and changes in rates unless a page says otherwise. Do not rely on a result here as medical, financial or legal advice.

Advertising

The site is free to use and is paid for by advertising served through Google AdSense. Advertisers have no influence on formulas or content. See the privacy policy for how advertising cookies work and how to turn off personalized ads.