Last updated: 8 November 2026
Sources and formulas
Each calculator is based on a standard mathematical formula or on an official rule published by the relevant authority (tax office, social security, central bank, health organisation…). The formula is shown on every page so you can check the result.
Testing
Before publication, every calculator is tested with worked examples in each language, including limit cases (zero, negative values, very large numbers). The example on each page is one of these tests.
Keeping figures up to date
Calculators that depend on figures that change (usury rate, minimum wage, tax scales, unemployment benefit…) show the date of the figures used. These figures are checked every quarter and updated when they change.
Corrections
If you report an error, we check it and correct the calculator and its page as quickly as possible.
Independence
No calculator is sponsored. Advertising, when present, never influences results or content.
Report an error
Use our contact form and choose “Report a calculation error”.