What we publish
Calculators, guides built on those calculators, reference tables generated from them, and reference pages such as the glossary and the list of formulas. Everything is published in English, French and Spanish.
Where the formulas come from
Calculators use standard published formulas: amortization for loans, Quetelet for body mass index, Mifflin-St Jeor for resting metabolism, and so on. None are invented here, and none are tuned to give a flattering answer.
See also:Formulas
How a calculator is written
Each calculator is one module of the engine. It declares its inputs with their units and valid ranges, applies its formula and returns the result together with the formula and the values substituted into it, so the arithmetic can be checked by hand.
A calculator is not published until its name exists in all three languages.
Testing
The engine is covered by an automated test suite that checks results against reference values. A change that breaks a tested result does not ship.
Guides and tables
Guides take every figure from the calculator they discuss: the numbers are computed when the site is built, not typed into the text. Reference tables are generated the same way. When a formula is corrected, the guides and tables that use it change with it.
See also:Blog
Independence
The site is funded by ads served by Google AdSense. Advertisers have no say over which calculators exist, which formulas they use or what the guides say. There are no sponsored calculators or guides.
Corrections
Report an error to [email protected]. A correction is checked against the formula's published source before the calculator is changed, and notable changes are listed in the changelog.
Limits
A formula is a model, not a verdict. Results are estimates based on the numbers you give, not financial, medical, legal or engineering advice.
See also:DisclaimerHow the calculators work