CNPJ Validator
Validate Brazilian CNPJ numbers instantly using the official algorithm. Useful for testing fiscal document validation. No data sent to servers.
How does CNPJ validation work?
A CNPJ has 14 digits: 8 identify the company, 4 indicate the branch (0001 for the headquarters) and the last 2 are check digits calculated by the Receita Federal using weighted multiplication with modulo 11.
A CNPJ is invalid if the check digits do not match the calculation, or if all digits are the same — such as "00.000.000/0000-00" — which passes the mask but fails the mathematical algorithm.
The check runs entirely in your browser. No CNPJ entered here is sent to servers.
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