Argentina CUIT Generator & Validator | Test Tax IDs
Generate and validate Argentina CUIT numbers for testing. Create mathematically valid tax IDs with correct check digits or verify existing CUITs instantly.
Argentina CUIT Generator & Validator
Generate mathematically valid Argentina CUIT numbers for testing or validate existing tax identification codes instantly.
CUIT Generator
CUIT Validator
Format: XX-XXXXXXXX-X
About CUIT
CUIT (Clave Única de Identificación Tributaria) is the tax identification number used in Argentina for individuals and legal entities.
- The format is XX-XXXXXXXX-X where X are digits.
- The first two digits indicate the type of entity (20 for male individuals, 27 for female individuals, 30 for companies, etc.).
- The last digit is a check digit, computed from the first 10 digits with a weighted mod-11 sum.
Documentation
What Is a CUIT?
A CUIT (Clave Única de Identificación Tributaria) is Argentina's tax identification number. ARCA, Argentina's federal tax and customs agency, uses it to identify self-employed workers, businesses and companies. ARCA (Agencia de Recaudación y Control Aduanero) replaced the former tax agency AFIP in October 2024. A CUIT is 11 digits long, written as XX-XXXXXXXX-X.
This calculator generates CUIT numbers that follow the official format and check-digit rule, and it checks whether an existing CUIT is mathematically valid. Numbers it generates are not registered with ARCA; they exist only for software testing, development, and teaching.
CUIT Structure and Type Codes
The 11 digits split into three parts.
| Part | Digits | Meaning |
|---|---|---|
| Type code | first 2 | Identifies the kind of taxpayer |
| Number | next 8 | A unique identifying number |
| Check digit | last 1 | Confirms the other 10 digits were entered correctly |
The type code shows what kind of entity holds the CUIT:
| Entity type | Type code used by this tool |
|---|---|
| Individual, male | 20 |
| Individual, female | 27 |
| Association | 33 |
| Company, foundation, society, government body, foreign company, or trust | 30 |
This tool gives companies, foundations, partnerships, government bodies, foreign companies and trusts the same code, 30. The prefix does not record the finer distinction between them; ARCA's registration records do.
How to Calculate the CUIT Check Digit
The check digit uses a weighted mod-11 checksum, the same family of method used by ISBN book codes and many other identification systems. It is built to catch typos and swapped digits, not to encode any hidden meaning.
Steps:
- Write the first 10 digits: the 2-digit type code followed by the 8-digit number.
- Multiply each digit by a fixed weight, in order: 5, 4, 3, 2, 7, 6, 5, 4, 3, 2.
- Add the 10 products together.
- Divide the sum by 11 and find the remainder.
- If the remainder is 0, the check digit is 0.
- If the remainder is 1, there is no valid check digit for that type code and number. This tool follows that rule: the generator quietly tries a new random number when this happens, and the validator marks any CUIT with this pattern as invalid, no matter what digit appears last.
- For any other remainder, the check digit equals 11 minus the remainder.
Worked Example
Calculate the check digit for type code 30 and number 12345678.
The first 10 digits are 3, 0, 1, 2, 3, 4, 5, 6, 7, 8. Multiply each by its weight and add the results:
(3×5) + (0×4) + (1×3) + (2×2) + (3×7) + (4×6) + (5×5) + (6×4) + (7×3) + (8×2) = 15 + 0 + 3 + 4 + 21 + 24 + 25 + 24 + 21 + 16 = 153
153 divided by 11 leaves a remainder of 10. 11 − 10 = 1.
The check digit is 1, so the full CUIT is 30-12345678-1.
For contrast, type code 20 with number 00000001 gives a sum of 12, which leaves a remainder of 1 when divided by 11. No check digit exists for that combination, so no valid CUIT can end that way under type code 20.
How the Validator Checks a CUIT
The validator runs two checks on the text entered.
- Format. The input must match XX-XXXXXXXX-X, or 11 plain digits with no separators; the tool adds the hyphens automatically.
- Check digit. The tool recalculates the check digit from the first 10 digits, using the steps above, and compares it to the last digit entered.
The validator does not check whether the 2-digit prefix is one that ARCA actually issues. A string such as 12-34567890-3 will pass if its checksum happens to be correct, even though 12 is not a taxpayer type code. Passing this validator confirms only that a number is arithmetically well-formed, not that ARCA issued it. To confirm registration, use ARCA's own Constancia de Inscripción lookup service.
Using the Generator and Validator
To generate a test CUIT, choose an entity type, such as company, individual or association, and select "Generate CUIT." The tool produces a randomly numbered CUIT with a correct check digit for that type.
To check a CUIT, type or paste it into the validator field and select "Validate CUIT." The result shows whether the format and check digit are both correct.
Numbers made by the generator are not registered with ARCA and do not identify any real taxpayer. They must not be used on a real tax filing, contract or invoice. Use generated CUITs only for software testing, staging environments and teaching.
CUIT vs CUIL
CUIT and CUIL share the same 11-digit format and the same check-digit algorithm. CUIT applies to taxpayers who run a business or work independently. The CUIL (Código Único de Identificación Laboral) is issued by ANSES, the social security agency. It is needed to start a job as an employee. A person who already has a CUIT does not need a separate CUIL.
Frequently Asked Questions
What is a CUIT number?
A CUIT is Argentina's tax identification number: 11 digits in the format XX-XXXXXXXX-X, assigned by ARCA to individuals and businesses that carry out formal economic activity.
Can this tool tell me if a CUIT is real?
No. It confirms only that a number is correctly formatted and that the check digit matches. ARCA's own registration records, not any offline calculation, determine whether a CUIT was actually issued. Use ARCA's Constancia de Inscripción service to confirm registration.
Can I use a generated CUIT on a real form?
No. Generated CUITs are mathematically valid but not registered with ARCA. They must not be used for a real filing, contract or invoice. Generated numbers are meant for software testing and teaching only.
Why does type code 30 cover so many kinds of entities?
The prefix only separates broad groups of taxpayers. In this tool, companies, foundations, partnerships, government bodies, foreign companies and trusts all get 30. The finer distinction is stored in ARCA's registration records, not in the CUIT itself.
Does the CUIT need hyphens?
No. The validator accepts both the hyphenated form (30-12345678-1) and the plain 11-digit form (30123456781); it inserts the hyphens itself before checking.
What is the difference between a CUIT and a CUIL?
Both use the same 11-digit format and check-digit method. CUIT identifies taxpayers running a business or working independently and is managed by ARCA. CUIL identifies employees and is issued by ANSES.
Do CUITs ever change?
A CUIT is normally permanent for its holder.
References
- Argentina.gob.ar (ARCA). Obtener CUIT por internet. Obtener CUIT por internet — CUIT stands for "clave única de identificación tributaria"; ARCA uses it to identify self-employed workers, businesses and companies.
- Poder Ejecutivo Nacional. Decreto 953/2024 (Boletín Oficial, 25 October 2024). Decreto 953/2024 — dissolves AFIP and creates ARCA as its legal successor.
- Argentina.gob.ar (ANSES). Obtener CUIL. Obtener CUIL — CUIL stands for "Código Único de Identificación Laboral"; needed to start work as an employee; not needed by holders of a CUIT.