Brazil CPF validator
How the CPF format works
- Format
- 11 digits
- Example
- 52998224725
Things to watch for
- 11 digits, the last 2 are mod-11 check digits
- Checksum only — does not confirm the person exists or is active
- Repeated-digit strings (e.g. 111.111.111-11) are always rejected
^[0-9]{11}$A CPF (Cadastro de Pessoas Físicas) is the 11-digit number Receita Federal, Brazil’s tax authority, assigns to every individual taxpayer — for example 529.982.247-25. It’s required for filing taxes, opening a bank account, or completing most contracts and purchases in Brazil, and it’s distinct from the CNPJ, which identifies companies rather than individuals.
The last 2 of the 11 digits are check digits, each generated by weighting the preceding digits and reducing the result modulo 11. That structure means a CPF isn’t just 11 random digits — a single mistyped digit almost always breaks the checksum, which is what makes a check like this useful before a form submission or a document gets rejected downstream.
How this validator works
This tool checks that the input is 11 digits and runs the two real mod-11 calculations Receita Federal uses to generate a CPF’s check digits, entirely in your browser. It also rejects repeated-digit strings like 111.111.111-11, which are never valid CPFs. Nothing is sent to a server, and there’s no signup.
What a pass doesn’t tell you
A pass confirms the number is a mathematically valid CPF — not that it belongs to a real, currently registered person, or that a name attached to it matches. Receita Federal can mark a CPF as irregular, suspended, or cancelled (for example, after a death is registered), and none of that status is visible from the digits alone.
Scope: this page and tool cover CPF format and checksum validation only — not registration status with Receita Federal or identity verification.
Content last reviewed 2026-07-07.
CPF FAQ
What is a CPF used for?
A CPF (Cadastro de Pessoas Físicas) is Brazil's individual taxpayer registry number, issued by Receita Federal. It's required to file taxes, open a bank account, sign an employment contract, or complete most retail and government transactions in Brazil.
Does a valid CPF checksum mean the person is registered with Receita Federal?
No. This tool only confirms the 11 digits pass the two mod-11 check-digit calculations used to generate every valid CPF — it doesn't confirm the number was ever issued to a real person or that their registration is currently active.
Why do numbers like 111.111.111-11 always fail?
CPF generation explicitly rejects sequences where all 11 digits repeat, so strings like 111.111.111-11 or 000.000.000-00 can never be a genuine CPF — this validator rejects them for the same reason.