RUC (Paraguay)

The Paraguayan RUC (Registro Único de Contribuyentes) is the tax identifier issued by SET (Subsecretaría de Estado de Tributación). It applies to natural persons, legal entities, associations, and state bodies. Structure: a base number of up to 8 digits followed by a hyphen and a check digit. Example: `4123456-7`. For natural persons the base number often matches the Cédula de Identidad; for companies it's a sequential number assigned by SET. The check digit is computed via modulo 11 with weights from 2 to 11 applied right to left over the base number: 1. For each digit (right to left), multiply by weight `2, 3, 4, ..., 11` (cyclic). 2. Sum all products. 3. Compute `sum mod 11`. 4. If remainder is 0, check digit = 0; if 1, check digit = 0 (special case); otherwise check digit = `11 - remainder`. Key differences from RUC Peru (11 digits, no hyphen) and RUC Ecuador (13 digits, structure by type): the Paraguayan one is shorter and simpler, with no encoded province or taxpayer type in the digits. Normadata validates format, length, and check digit. Confirming existence requires querying SET's Marangatu system.