How to use
- 1Paste the CPF in the main field.
- 2Click Process.
- 3See whether the CPF is valid or invalid.
About
Validates the format and verification digits of a CPF in real time, without sending the data anywhere. Great for forms and systems that need to verify CPFs.
How to validate a CPF correctly
The CPF validator checks whether an 11-digit number is structurally valid by applying the official two-check-digit algorithm. It is the first filter for catching typos before sending data to a system.
A CPF has 11 digits: the first 9 form the base number and the last 2 are check digits, calculated with the modulus 11 algorithm. The tool redoes this calculation to confirm the number is well formed.
It is essential to understand the difference between valid and existing. A CPF can pass the algorithm (correct structure) and still not belong to anyone, because the algorithm only validates the math, not the registration with the Brazilian revenue service.
The validation also rejects obvious sequences like 111.111.111-11 or 123.456.789-09, which would pass the check digit but are not real CPFs. This extra care avoids false positives.
Examples
- 529.982.247-25 → valid (check digits match).
- 111.111.111-11 or 529.982.247-20 → invalid (repeated sequence or incorrect digit).
Limitations
- Validation is structural: it confirms the math of the digits, but does not query the Brazilian revenue service to know whether the CPF exists or is active.
- Using valid generated CPFs for testing in real registrations is illegal and may constitute fraud.
How to use the CPF validator
- 1Type or paste the CPF (with or without dots and hyphen).
- 2Click Process.
- 3See whether it is valid or invalid.
Frequently asked questions
Does a valid CPF in the algorithm always exist?
No. The algorithm confirms the mathematical structure. Real existence depends on a query to the Brazilian revenue service, which this tool does not perform.
Can I use it with or without punctuation?
Yes. The tool accepts the number with dots and hyphen (529.982.247-25) or just the 11 digits (52998224725).
Why is 111.111.111-11 rejected?
Because these are repeated sequences. Although they pass the calculation, they do not correspond to real CPFs and are filtered out to avoid false valids.