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.

CNPJ validator

Both CNPJ check digits, letters too.

Examples temporarily replace the input and settings. You can restore your previous work.

Input0 characters

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 What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.

Example

Worked example — CNPJ validator

Use the following inputs and settings. Keep other settings at the page defaults.

Item	Value
Input	11.222.333/0001-81
kind	cnpj
Output	✓ 11.222.333/0001-81 — valid CNPJ
Output	1st check digit: 1×5 + 1×4 + 2×3 + 2×2 + 2×9 + 3×8 + 3×7 + 3×6 + 0×5 + 0×4 + 0×3 + 1×2 = 102
Output	102 ÷ 11 = 9 remainder 3 → 11 − 3 = 8 ✓
Output	2nd check digit: 1×6 + 1×5 + 2×4 + 2×3 + 2×2 + 3×9 + 3×8 + 3×7 + 0×6 + 0×5 + 0×4 + 1×3 + 8×2 = 120
Output	120 ÷ 11 = 10 remainder 10 → 11 − 10 = 1 ✓
Output	A correct check digit only means the number is well-formed; it doesn’t mean the number exists or belongs to anyone. Nothing is sent anywhere: the check runs in your browser.

Expected result — ✓ 11.222.333/0001-81 — valid CNPJ

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.