Methodology
This page describes the process behind every Contania calculator: where the numbers come from, how formulas are verified, and what we do when something changes — or when we get it wrong.
Where the numbers come from
Every calculator starts from a hierarchy of sources: legislation and official tables first, then technical standards and reference literature, then consolidated educational material. The sources are listed on each calculator's page, linked when available. When a computation admits more than one accepted method (like the several ideal-weight formulas), the page says which method it uses and why.
How a formula becomes a calculator
The formula is implemented in code and verified by automated tests that compare results against independently computed cases — including the edge cases where most errors live (zero, negatives, table caps and floors, bracket rounding). Beyond the result, each page builds the calculation trace: the formula applied and the step-by-step with your values, so any result can be checked by hand.
Updates and reference years
Calculators that depend on time-bound tables — taxes, contributions, minimum wage — display their reference year explicitly (e.g. “2026 tables”) and answer the “is this up to date?” question directly in the FAQ. When a table changes, the calculator is updated and its revision date moves with it. Revision dates on this site are real: they only change when the content actually changes.
Rounding and precision
Monetary results follow the Brazilian standard of two decimal places; percentages and measures use precision appropriate to the quantity. Where a norm defines the rounding rule (as in tax brackets), we follow the norm; where it doesn't, we round only at the end, never in intermediate steps — and the calculation trace shows the values used.
What the calculators are not
They are educational, estimate-making tools — not a substitute for an accountant, lawyer, physician, nutritionist or engineer. Health and safety pages carry specific notices and avoid anything resembling a prescription; finance and legal pages recommend confirming with a qualified professional and official sources. No Contania page is paid to push a decision.
Errors and corrections
When an error is confirmed — via reader report or internal review — the fix follows three steps: correct the formula or text, record a new revision date on the page and, when the error was material, explain the change to whoever reported it. To report one, write to contato@contania.app with the link and the values used (the format is on the Contact page).
Advertising and independence
Contania is funded by labeled advertising. Advertisers have no say in topics, formulas or texts, and no calculator result is influenced by ads. Ad slots are identified and separated from content, and advertising cookies are only activated with your consent, as described in the Privacy Policy.