Validators

CNPJ Validator

Check if a Brazilian CNPJ is valid using verification digits.

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How to use

  1. 1Paste the CNPJ in the field.
  2. 2Click Process.
  3. 3See whether it is valid or invalid.

About

Checks the format and verification digits of a CNPJ, all locally in the browser. Useful for validating data in registrations and integrations.

How to validate a CNPJ correctly

The CNPJ validator checks whether a 14-digit number is structurally valid by recalculating the two check digits using the official modulus 11 algorithm. It helps review registrations before issuing invoices or closing contracts.

A CNPJ has 14 digits: the first 8 identify the company, the next 4 represent the branch/order, and the last 2 are check digits. The tool redoes the calculation of those last two to validate the structure.

As with the CPF, validating the CNPJ only confirms the math. A number can pass the algorithm and not correspond to any active company, since real existence requires a query to the Brazilian revenue service.

The tool also blocks repeated sequences (like 11.111.111/1111-11) that would fool the calculation, delivering a more reliable result for registrations and integrations.

Examples

  • 11.222.333/0001-81 → valid (check digits match).
  • 11.222.333/0001-80 → invalid (incorrect check digit).

Limitations

  • Validation is structural: it does not query the Brazilian revenue service to confirm registration status, activity, or company existence.
  • The format may vary in specific cases (MEI uses its own CNPJ), but the 14-digit structure is the same.

How to use the CNPJ validator

  1. 1Type or paste the CNPJ (with or without punctuation).
  2. 2Click Process.
  3. 3See whether it is valid or invalid.

Frequently asked questions

Does a valid CNPJ in the algorithm always exist?

No. The algorithm validates the mathematical structure. Existence and company status depend on a query to the Brazilian revenue service.

Does MEI have a CNPJ?

Yes. The Individual Microentrepreneur has a CNPJ with the same 14-digit structure, validated the same way.

Can I validate without punctuation?

Yes. The tool accepts both the masked format (11.222.333/0001-81) and just the 14 digits.

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