How to validate CNPJ
Enter the number and validate. Ontoom checks both check digits without querying the tax authority. To generate a new test number, use the CNPJ generator.
Ontoom
CNPJ validator
Validate CNPJ check digits (with or without mask).
CNPJ
Important: Synthetic data for testing. Misuse is the user's responsibility.
Need to create a synthetic CNPJ? CNPJ generator.
Frequently asked questions
- Does validating a CNPJ confirm the company exists?
- No. The check is only of check digits and format.
- Does it accept masked CNPJ?
- Yes. Paste with or without punctuation; the tool normalizes the digits.
- Why is my CNPJ invalid?
- Wrong check digits, wrong digit count, or an invalid sequence (e.g. all identical).
- Where can I generate a test CNPJ?
- In Ontoom’s CNPJ generator, then come back here to validate manual entries.