Updated: July 2026
CPF Validator is a free online tool that instantly checks whether a CPF number is valid. Also called CPF validation or CPF validator, it serves the same purpose: you type or paste the number, with or without punctuation, and the tool tests the two check digits using the same algorithm used by the Federal Revenue Service. If the CPF passes the verification, it still shows the state of origin of the number, indicated by the 9th digit.
What it is (and what this validator does not check)
Validation takes place in three checks:
- Format: the number must have exactly 11 digits.
- Repeated sequences: numbers like 111,111,111-11 are rejected. They even pass the check digits count, but they do not correspond to real CPFs and every serious system blocks them.
- Check digits: the last two digits are recalculated from the first nine. If the account does not match, the CPF is invalid.
It is important to understand the tool's limits: a valid CPF is a number that respects the mathematical rule, not necessarily a CPF that exists. The validator does not consult the Federal Revenue database and does not provide the name, registration status or who the number belongs to. To find out if a CPF is in good standing, use the official Federal Revenue Service registration status query.
How to use
- Type or paste the CPF in the field, with or without dots and dashes. Punctuation is automatically applied as you type.
- Click validate or press Enter.
- See the result: the tool informs you whether the number is valid and, when it is, shows the tax region (state) of origin.
Everything happens directly in your browser: the number you enter is not sent or stored on any server.
What is the purpose of validating a CPF
- Check typing before saving a registration or issuing a document.
- Test forms and systems, checking whether your validation accepts correct numbers and rejects wrong numbers.
- Clean databases, identifying records with impossible CPF.
- Discover the state of origin of a number, using the tax regions table.
- Check a CPF that came from elsewhere: as the check is just mathematics, it works with any number, it doesn't matter if it came from a spreadsheet, a system or a test CPF generator.
Do you need the opposite way, creating fictitious numbers to test your system? Use the CPF Generator, which assembles mathematically valid CPFs in batch, with formatting and choice of state.