Cédula de Identidad (CI) Validator (Uruguay)
Validate authenticity and official check digits for Uruguayan Cédula de Identidad (DNIC).
How does validation work?
The Cédula de Identidad (CI) is the civil identity document issued by the National Civil Identification Directorate (DNIC) in Uruguay.
The check digit is calculated by multiplying the first 7 digits by fixed weights [2, 9, 8, 7, 6, 3, 4] and applying Modulo 10.
Anatomy & Structure of Uruguayan Cédula de Identidad
The civil ID (CI) issued by the DNIC comprises 2 functional sections:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 7 | Base Sequential Number | 6 to 7 digits | Sequential civil registration number (left-padded with zeros to 7 digits if < 1,000,000) | 1234567 |
| Final (after hyphen) | Check Digit (DV) | 1 digit | Modulo 10 checksum with positional factors [2, 9, 8, 7, 6, 3, 4] | 8 |
Official CI Validation Algorithm (DNIC Modulo 10)
The DNIC applies a fixed sequence of factors over the 7-digit padded base:
DV = (10 - (Σ (d[i] × [2, 9, 8, 7, 6, 3, 4][i])) % 10) % 10
- 1. Left-pad sequential base with zeros until reaching exactly 7 digits.
- 2. Multiply each of the 7 digits by the fixed weights: [2, 9, 8, 7, 6, 3, 4].
- 3. Sum all products.
- 4. Remainder = Sum % 10.
- 5. Check digit = (10 - Remainder) % 10.
- 6. Document is authentic if check digit matches the trailing digit.