International · Argentina
Argentina CUIT / CUIL validator.
Validar CUIT online: check an 11-digit CUIT or CUIL against its check digit, or calculate a CUIL from a DNI. Everything runs in your browser.
How it works: the first 10 digits are multiplied by 5, 4, 3, 2, 7, 6, 5, 4, 3, 2 and added up. The sum modulo 11 gives the remainder r. The check digit is 11 minus r, except r=0 gives 0 and r=1 gives 9.
Inputs
Calculate a CUIL from a DNI
Result
Enter a CUIT or CUIL and press Check.
How the CUIT / CUIL check digit works
A CUIT (Clave Única de Identificación Tributaria) or CUIL (Código Único de Identificación Laboral) has 11 digits: a two-digit type, eight digits that are the holder's DNI (or a company number), and a check digit. Both use the same calculation.
| Step | What happens |
|---|---|
| 1 | Multiply the first 10 digits by the weights 5,4,3,2,7,6,5,4,3,2 and add them up |
| 2 | Take the sum modulo 11 (remainder r) |
| 3 | Check digit = 11 − r; if r is 0 the digit is 0; if r is 1 the digit is 9 |
Worked example: 20-12345678 gives a sum of 148, remainder 5, check digit 6, so 20-12345678-6. The python-stdnum test number 20-05536168-2 is also valid.
When the remainder is 1
Following the Spanish Wikipedia description, when a personal number would give remainder 1 the type changes to 23 and the digit is 9 for a man (originally 20) or 4 for a woman (originally 27). The calculator applies this and tells you when it did. The result is checksum-consistent, so the validator accepts it.
Type prefix is not enforced
Our two sources list different type prefixes (python-stdnum also has 50, 51 and 55; Wikipedia also lists 25 and 26), so this tool does not reject a number for its prefix. It only notes when the prefix is one of the common ones both sources list: 20, 23, 24, 27 (individuals) and 30, 33, 34 (companies).
Checksum check only, not an ARCA lookup
A passing result means the digits are internally consistent. It does not confirm the number was issued, is active, or belongs to anyone; only ARCA (formerly AFIP) can confirm that. A CUIL calculated from a DNI is a calculation, not proof the person has one.
Sources
python-stdnum, stdnum/ar/cuit.py (weights, check digit table, test numbers). Wikipedia (es), Clave Única de Identificación Tributaria (procedure, worked example, remainder 1 rule). We did not find an ARCA page stating the rule, so it rests on these two sources.
Checksum only — not an ARCA lookup
This tool checks the modulo 11 check digit entirely in your browser. A checksum-valid result is not proof the number was ever issued or belongs to anyone. Nothing you type is transmitted, stored, or logged.