🇦🇷 ARGENTINA · WORKER ID
CUIL validator (free)
The CUIL (Código Único de Identificación Laboral) is the 11-digit worker identifier issued by ANSES in Argentina. It shares the same Mod-11 algorithm as CUIT but is restricted to individual prefixes. This tool validates format and check digit client-side.
Validates locally — your data never leaves your browser. No tracking on input. Format and check-digit validation only.
Validates locally — your data never leaves your browser. No tracking on input.
How CUIL validation works
A CUIL has 11 digits: a 2-digit prefix that identifies the worker class (20 male, 23/24/25/26 dual or special, 27 female), an 8-digit base derived from the DNI, and a single check digit. CUIT and CUIL share the same algorithm but CUIL excludes company prefixes (30, 33, 34).
The check digit uses Mod-11 with weights [5, 4, 3, 2, 7, 6, 5, 4, 3, 2] over the first 10 digits. Compute the weighted sum, take modulo 11, subtract from 11. Remainder 0 → check 0; remainder 1 → invalid; otherwise the check digit is 11 − remainder.
This tool also rejects repeated-digit sequences (e.g., 27-00000000-0) and any prefix outside the worker range. It does not query ANSES to confirm the worker is active.
Frequently asked questions
What is the difference between CUIT and CUIL?
CUIT (issued by AFIP) identifies any taxpayer including companies; CUIL (issued by ANSES) identifies workers in the social-security system. They use the same 11-digit format and Mod-11 algorithm, but CUIL prefixes are restricted to 20, 23, 24, 25, 26, 27 — never company prefixes (30, 33, 34).
Can a person have both a CUIT and a CUIL?
Yes. A self-employed individual has both — typically with the same digits — because they need a CUIT for tax purposes and a CUIL for social-security contributions.
Does this validator confirm the CUIL is registered with ANSES?
No. It validates format and check digit only. Confirming an active CUIL requires a query to ANSES's official registry, which this tool does not perform.
Can I validate CUIL via API?
Yes. Normadata's Verify API accepts CUIL alongside CUIT and 20+ other Latin American identifiers with a single JSON call.
More resources
Want CUIL validation in your app?
The Normadata Verify API validates CUIL alongside CUIT, DNI, CBU and 20+ Latin American identifiers with a single JSON call.
See the Verify API→