Methodology

This page explains how Ferramenta Grátis is made: where the calculations and tables come from, who is responsible for the content, how often we update the data and how you can report an error. Our commitment is to be honest about what each tool does and what it does not do.

Where the formulas and tables come from

The tools use public formulas and official sources. Whenever a calculator depends on a rule, table or index, we look for the primary reference. The main sources by area are:

• Documents (CPF, CNPJ, RG, PIS, voter ID, RENAVAM, etc.):{' '} public check-digit algorithms (modulo 11 and variations). The numbers generated are valid only in format and check digits, are fictitious and are not looked up in any official database.
• Labor (severance, 13th salary, vacation): rules from the{' '} Consolidation of Labor Laws (CLT){' '} and INSS and IRRF tables published by the{' '} Receita Federal (Brazil's federal tax authority){' '} and by{' '} Previdência Social (Brazil's social security).
• Health (BMI, pregnancy): BMI classification from the{' '} World Health Organization (WHO){' '} and reference parameters from the{' '} Ministério da Saúde (Brazil's Ministry of Health).
• Financial and conversions: standard mathematical formulas. When there is a live currency rate, it comes from a public API and represents the market exchange rate, not the official PTAX rate of the Central Bank of Brazil.
• Math and unit conversion: conversion factors and formulas from the International System of Units (SI).

On pages where the source matters for trust in the result, it is linked in the tool's own content.

How the tools are built

Almost all tools work entirely in your browser. The text, numbers, images and files you use are processed on your own device and, as a rule, are not sent to or stored on our servers. This applies to image conversion, PDF handling and test document generation. When a tool needs external data (such as a currency rate), this is stated on the page itself.

Each tool is tested before going live. Document generators, for example, are checked by cross-validation: the generated number always passes the matching validator, and changing a single digit makes validation fail.

Who maintains the content

Ferramenta Grátis is a project of TempusTech (tempustech.com.br), under the responsibility of André Baumer. The content and tools are produced and maintained by our editorial team.

On sensitive topics, known as YMYL ("Your Money or Your Life"), such as labor, financial and health calculations, we base each tool on official sources: laws on{' '} Planalto (Brazilian federal legislation), tables from the{' '} Receita Federal{' '} and the{' '} INSS, references from the{' '} WHO{' '} and the{' '} Ministry of Health,{' '} which are linked on the page itself. These are informational tools: they have not been reviewed by a credentialed professional (accountant, lawyer or health professional) and do not replace that guidance. We prefer to say so clearly rather than pretend to a credential we do not have.

How often we update

We review the tools periodically and whenever a rule changes, for example, when the INSS and IRRF tables are updated at the start of the year. The relevant update dates appear on critical tools. If you notice that a table or index is out of date, let us know.

How to report an error

If a result looks wrong, if a table is out of date or if you find any problem, write to us through the{' '} Contact page. Corrections suggested by people who use the site are one of the fastest ways for us to improve the quality of the tools.

Our limits

The tools are informational and do not replace the guidance of a qualified professional or approved official values. Always check the notices shown on each tool and read our{' '} Terms of Use.