What changes in the alphanumeric CNPJ?

It still has 14 characters and the same mask, XX.XXX.XXX/XXXX-XX. The first 12, which hold the root and the establishment order, now accept letters A to Z besides digits. The last two, the check digits, are always numeric. The Receita Federal has assigned this format to new registrations since July 2026, and existing CNPJs do not change.

How do letters enter the check digit calculation?

Each character becomes its ASCII code minus 48. Digits keep their value and letters are worth A=17, B=18 up to Z=42. Then the usual Modulo 11 applies, with weights from 2 to 9 from right to left. If the remainder of the division by 11 is 0 or 1, the digit is 0. Otherwise it is 11 minus the remainder.

What is the official example to test my system?

The Receita Federal manual uses 12.ABC.345/01DE-35. The first 12 characters add up to 459 in the first calculation, remainder 8 and first digit 3. With that 3 included, the sum is 424, remainder 6 and second digit 5. The example button fills in this CNPJ for you.

Does the validation accept lowercase, dots and spaces?

Dots, slash, hyphen and spaces are ignored anywhere in the value. Lowercase letters are converted to uppercase and the result tells you when that happens, because the official CNPJ is uppercase only. Any other character, such as an accent, underscore or comma, is rejected and pointed out.

Are all letters of the alphabet accepted?

Yes. The Receita Federal guidance is that systems accept all 26 letters from A to Z. It avoids issuing some combinations that would spell offensive words, but that is control at issuance and does not change validation.

Does a CNPJ that is valid here exist at the Receita Federal?

Not necessarily. The check is mathematical, so a number built by a generator passes if the digits match, even if it was never issued. Knowing whether a company exists and is active requires querying the official databases.

Is the CNPJ I type sent or stored?

No. The calculation runs in the browser and the number goes to no server, not to the page address and not to browser storage. In our metrics we only record how many CNPJs were validated and how many were valid, never the numbers themselves.

Numeric and Alphanumeric CNPJ Validator

Check whether a CNPJ passes the Receita Federal rule, whether it is the classic numeric one or the alphanumeric format issued since July 2026. When it fails, you see why.

Result

Type or paste a CNPJ and click validate.

Need valid CNPJs to test with? Generate them in the numeric or alphanumeric format.

Generate CNPJ

Validating a CNPJ in a form or extracting it from a log?See the CNPJ regex

What this validator checks

The validator checks whether a CNPJ has the structure defined by the Receita Federal: 14 characters, only digits 0 to 9 and letters A to Z in the first 12, and two numeric check digits that match the calculation.

It detects on its own whether the number is numeric or alphanumeric, so it works for the CNPJ you already use and for the new format your application needs to accept.

When a CNPJ fails, the result says why: a character that cannot exist, wrong length, a check digit that is not a number or digits that do not match, with the expected value next to the informed one.

How the Receita Federal calculates the check digits

The calculation uses the first 12 characters and Modulo 11, and the alphanumeric CNPJ only changes how letters are converted.

Step by step:

Replace each character with its ASCII code minus 48. Digits stay as they are and letters go from A=17 to Z=42.
Multiply by the weights 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2 and add everything up.
Divide the sum by 11. If the remainder is 0 or 1, the first digit is 0. Otherwise it is 11 minus the remainder.
Append the first digit, use the weights 6, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2 and repeat the calculation to get the second.

In the official example, 12ABC34501DE gives the digits 35, forming 12.ABC.345/01DE-35.

When to use it

Situations where checking the digit right away saves you from hunting the bug in code:

Adapting your system to the new format

Test whether your registration form, API and database accept letters in the first 12 characters and reject what the Receita Federal rejects.

Checking test data

Paste the QA list of CNPJs, one per line, and see which ones have a wrong check digit before running the suite.

Debugging a rejection

Find out whether a CNPJ was refused because of length, a hidden character or the check digit.

Comparing with your own validation

Use the expected digit as a reference to confirm your function calculates the same as the Receita Federal manual.

Frequently Asked Questions about the CNPJ Validator

Answers for people who need to accept or test the alphanumeric CNPJ in their system.