Brazilian CPF Validator
Enter a CPF, formatted or not, and see whether its check digits are valid.
This tool validates Brazilian documents only.
Not sure? Turn your internet off and try — it still works.
How it works
The CPF has 11 digits, written 000.000.000-00. The first 9 are the person's base number (the ninth digit points to the tax region where the CPF was registered) and the last 2 are check digits, calculated with modulo 11 from the ones before. A worked example with the test number 111.444.777-35: multiply each of the first 9 digits by weights from 10 down to 2 and add them up (1×10 + 1×9 + 1×8 + 4×7 + 4×6 + 4×5 + 7×4 + 7×3 + 7×2 = 162); multiply the sum by 10 and take the remainder of the division by 11 (1,620 mod 11 = 3) to get the first check digit, 3. The second digit comes from the same calculation over the first 10 digits, with weights from 11 down to 2, and gives 5. Typical use: double-checking a CPF before submitting a form, a sign-up or an invoice. A CPF with correct check digits does not prove the number was ever issued to someone or that the person exists: this tool checks only the format and the digits, without asking the Receita Federal.