South Korean RRN Validator
Validate South Korean Resident Registration Numbers (RRN) in real time.
South Korean RRN Validation
Validates the 13-digit format, checking birth date consistency, gender digit, and weighted modulo 11 checksum.
Ensures compliance for Korean user onboarding and identity verification software.
Anatomy & Structure of the RRN (주민등록번호 / Resident Registration Number)
The South Korean Resident Registration Number consists of 13 digits in 5 parts:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 6 | Birth Date | 6 digits | Date in YYMMDD format | 900307 |
| 7 | Gender & Century | 1 digit | 1/2=20th century (M/F), 3/4=21st century (M/F), 5-8=Foreigners | 1 |
| 8 to 11 | Registration Office | 4 digits | Local registration office code (randomized since Oct 2020) | 2345 |
| 12 | Sequential Number | 1 digit | Differentiates individuals with same birth/location | 6 |
| 13 | Check Digit | 1 digit | Calculated via Modulo 11 with specific weights | 7 |
Official Algorithm (Modulo 11 — Resident Registration Act)
Official check digit calculation for South Korean RRN:
S = Σ d[i] × W[i] (i=1..12); DV = (11 - (S mod 11)) mod 10
- 1. Multiply the first 12 digits by weights: W = [2, 3, 4, 5, 6, 7, 8, 9, 2, 3, 4, 5].
- 2. Sum all products into total S.
- 3. Calculate remainder of S divided by 11.
- 4. Subtract remainder from 11 and apply modulo 10: DV = (11 - remainder) mod 10.
- 5. The RRN is valid if the 13th digit matches the calculated check digit.