How formulas, assumptions, examples and test cases are used to develop and check the calculators.
Each calculator identifies its inputs, units, formula and intended use. Defaults are examples unless a named jurisdiction and source specify otherwise. Rate conventions and endpoint counting rules are stated where they change the result.
Checks cover independently known examples, zero values where valid, rejected invalid inputs, date boundaries and unit conversions. Interface checks cover forms, menu navigation and mobile layout. Tests reduce mistakes but cannot prove every possible input is error-free.
A fixed conversion factor is different from a current tax schedule or lending policy. Official sources are linked for jurisdiction-specific claims. Publication dates describe this edition; they are not an assurance that all external rules will remain unchanged.
Worked examples can be loaded into the relevant forms and downloaded as JSON. To report an issue, include the URL, chosen mode, non-sensitive input values, expected result and result received. Confirmed corrections should update both the calculation and its example when affected.
Download the worked-example inputs as JSON. The file identifies each tool and the page explaining its example.
English edition: 16 September 2026.