CUIT Validator

About this calculator

A CUIT (Código Único de Identificación Tributaria) is Argentina's unique tax identification number, issued by the AFIP (now ARCA) tax authority to every person and company that needs to file taxes, invoice clients, or register a business. It's an 11-digit number formatted as XX-XXXXXXXX-X, where the first two digits (the “prefix”) indicate the entity type — for example 20 or 23 for a male individual, 27 for a female individual, and 30 or 33 for a company — and the final digit is a check digit computed with a mod-11 algorithm.

This validator recomputes that check digit from the first ten digits and confirms whether a given CUIT is structurally valid, while also reading the prefix to report whether it belongs to a person or a company. It's used by accountants, invoicing and e-commerce systems, and Argentine businesses to catch typos and reject malformed tax IDs before they're used on an invoice or tax filing.