RUT Tax Number Validator (Uruguay)
Validate 12-digit structure and Modulo 11 check digits for corporate tax entities registered with DGI Uruguay.
How does validation work?
The Registro Único Tributario (RUT) is the 12-digit corporate tax identification number issued by DGI in Uruguay.
Structured as [2-digit department/type code (usually 21)] + [6-digit sequential] + [3-digit branch code (001)] + [1 Mod 11 check digit with weights 4,3,2,9,8,7,6,5,4,3,2].
Anatomy & Structure of Uruguay RUT DGI
The 12-digit corporate tax registration number (RUT) issued by Uruguay's DGI is structured as follows:
| Position | Field | Length | Meaning & DGI Rule | Example |
|---|---|---|---|---|
| 1 & 2 | Department | 2 digits | 01-18 for regional departments; 21 designates Montevideo (corporate entities). | 21 |
| 3 to 8 | Sequential Number | 6 digits | Sequential corporate taxpayer ID allocated by DGI. | 317103 |
| 9 to 11 | Branch Code | 3 digits | 001 represents the primary headquarters (Matriz); 002+ indicates branch offices. | 001 |
| 12 | Check Digit | 1 digit | Modulo 11 check digit using DGI weights [4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2]. | 4 |
DGI Modulo 11 Validation Algorithm (Uruguay)
The 12th check digit is calculated according to the official DGI specification:
Remainder = (Σ (d[i] × Weight[i])) % 11 (Rem 0 = 0, Rem 1 = 6, else 11 - Rem)
- 1. Official Positional Weights: multiply the first 11 digits by weights [4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2].
- 2. Sum and Modulo 11: sum all 11 products and calculate the integer remainder by 11.
- 3. Specific DGI Rule: if remainder is 0, check digit is 0. If remainder is 1, check digit is 6. For any other remainder, check digit is 11 minus remainder.