Argentina CUIT / CUIL Validator
Check an Argentine CUIT or CUIL with the official modulo-11 check digit and detect whether it is an individual or company. 100% local. Built for Argentina.
Batch check — paste many, one per line
Validate a CUIT/CUIL
Paste an 11-digit CUIT or CUIL (hyphens optional) to check its modulo-11 check digit and see whether it is an individual or company.
Argentina's CUIT (companies and self-employed) and CUIL (employees) are 11-digit codes in the form XX-XXXXXXXX-X: a 2-digit type prefix, an 8-digit base (usually the DNI for individuals), and one check digit. The check digit uses weights 5-4-3-2-7-6-5-4-3-2 modulo 11, as defined by the tax authority AFIP (renamed ARCA in late 2024). This tool validates the prefix, recomputes the check digit locally, and explains any mismatch.
Common prefixes: 20 (men), 27 (women), 23/24 (shared/collision cases) for individuals; 30 and 33/34 for companies and other entities. A valid CUIT/CUIL structure does not prove the taxpayer exists or is active — for registry status use ARCA's official "Constancia de Inscripción" service. Last verified: July 2026.
FAQ
How does the mod-11 check work, step by step?
Multiply the first 10 digits by 5,4,3,2,7,6,5,4,3,2 and sum. Compute 11 − (sum mod 11): if the result is 11 the check digit is 0; if it is 10, the number is reassigned with prefix 23 instead (there is no check digit "10"); otherwise the result itself is the check digit.
What is the difference between CUIT and CUIL?
Same format, same math, different role: CUIL identifies employees for social security (issued by ANSES); CUIT identifies taxpayers (issued by AFIP/ARCA). A self-employed person’s CUIT usually equals their CUIL.
Why do some people have prefix 23?
Prefix 23 (and 24) resolves collisions — including the historical case where the standard formula would yield 10 as a check digit, which the system does not use.
Can I check a payroll list at once?
Yes — batch mode takes one number per line, tolerates dots/dashes/spaces, and returns per-row verdicts with reasons plus CSV export. Everything stays on your device.