CNPJ validator
Both CNPJ check digits, letters too.
Output
Paste or type above to see the result here.
Your files stay on your device
This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
How it works
- Paste one number a line; dots, dashes and spaces are fine.
- Each is checked for its length and its check digits.
- The result shows each step of the calculation, and where a number fails.
Frequently asked questions
- How are the CNPJ check digits calculated?
- The first twelve characters are multiplied by 5 4 3 2 9 8 7 6 5 4 3 2 and summed; the remainder divided by 11 gives the first check digit; the second adds one more weight.
- What is the alphanumeric CNPJ?
- From July 2026 new CNPJs may have letters in the first twelve positions (IN RFB 2.229/2024). Each character counts as its ASCII code minus 48, so A is 17; the check digits stay numeric.
- Does a valid check digit mean the number exists?
- No — only that it is correctly written. Whether it was issued, and to whom, only the issuing authority can say. The checker never makes up numbers either: it checks the ones you type.
- Is anything uploaded?
- No. The check is worked out in your browser, and nothing you type leaves your computer.