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, the national tax and customs agency, assigns a CUIT to every person and business that carries out formal economic activity, such as opening a bank account, signing an employment contract, or issuing an invoice. ARCA replaced AFIP in October 2024 and took over the same job. 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 |
|---|---|
| Individual, male | 20 |
| Individual, female | 27 |
| Association | 33 |
| Company, foundation, society, government body, foreign company, or trust | 30 |
Six of the entity choices in this tool share the single code 30: company, foundation, society, government body, foreign company, and trust. The finer distinction between them lives in the tax agency's registration records, not in the CUIT number itself. Argentina uses a few further prefixes that this generator does not offer, among them 23, 24 and 34.
How to Calculate the CUIT Check Digit
The check digit uses a weighted mod-11 checksum. The same kind of method appears in ISBN book codes and many other identification numbers. It catches typos and swapped digits. It carries no hidden meaning of its own.
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, no single digit can finish the number under that type code. Argentina resolves this by issuing the number under a different prefix instead: 20 and 27 become 23, and 30 becomes 33. This tool follows the same rule. The generator draws a fresh random number when it hits this case, and the validator marks any CUIT with this pattern as invalid, whatever 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 12,345,678.
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. The same number works under prefix 23: the sum becomes 24, the remainder is 2, and the check digit is 9, giving 23-00000001-9.
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 Argentina actually uses. A string such as 12-34567890-3 passes, because its checksum is correct, even though no entity type carries the prefix 12. Passing this validator confirms only that a number is arithmetically well-formed, not that ARCA issued it. To confirm registration, use ARCA's 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, then 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. Using one on a real tax filing, contract, or invoice would be fraud under Argentine law. 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. A CUIT identifies taxpayers who run a business or work independently, and ARCA assigns it. A CUIL (Código Único de Identificación Laboral) identifies employees working under a labour contract, and ANSES, the national social security administration, assigns it. Many Argentine forms accept either number, because the digits and the validation rule are identical. The records behind them sit in different agencies.
Background
Law 23,495 created the CUIT in 1987, when the Dirección General Impositiva (DGI) collected Argentina's taxes. Its use became compulsory before every national government body in August 1998. Decree 1156/96 merged the DGI with the customs administration into AFIP, which finished forming in July 1997 and ran the CUIT system for the next 27 years. Decree 953/2024 dissolved AFIP in October 2024 and handed its duties to ARCA. Today, opening a business bank account, signing most employment contracts, or issuing an electronic invoice in Argentina requires a CUIT.
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 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. Using one for a real filing, contract, or invoice is fraud under Argentine law. Generated numbers are meant for software testing and teaching only.
Why does type code 30 cover so many kinds of entities?
The code 30 covers companies, foundations, societies, government bodies, foreign companies, and trusts alike. The finer distinction between them sits in ARCA's registration database, 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.
Do CUITs ever change?
A CUIT is normally permanent for its holder. ARCA updates or reissues one for reasons such as a legally recognised gender change, a company merger, or confirmed identity theft.