South Korean BRN Generator
Generate and format valid South Korean Business Registration Numbers (BRN) for corporate QA testing.
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About the South Korean BRN
The BRN (Business Registration Number / 사업자등록번호) is the 10-digit tax identification number issued to businesses by the National Tax Service (NTS) of South Korea.
It follows the 3-2-5 pattern and features a specialized weighted modulo 10 checksum algorithm.
Anatomy & Structure of the BRN (사업자등록번호 / Business Registration Number)
The South Korean Business Registration Number consists of 10 digits structured in 4 parts:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 3 | Tax Office Code | 3 digits | Regional Tax Office code of issuance | 123 |
| 4 & 5 | Business Type | 2 digits | 01-79=Sole proprietor (VAT), 80=Non-profit, 81-99=Corporations | 45 |
| 6 to 9 | Sequential Number | 4 digits | Unique registration sequence assigned by NTS | 6789 |
| 10 | Check Digit | 1 digit | Calculated via Modulo 10 with 9th digit tens adjustment | 0 |
Official Algorithm (Weighted Modulo 10 — NTS Korea)
Official check digit calculation for South Korean BRN:
S = Σ (d[i]*W[i]) + floor(d[9]*5 / 10); DV = (10 - (S mod 10)) mod 10
- 1. Multiply the first 9 digits by weights: W = [1, 3, 7, 1, 3, 7, 1, 3, 5].
- 2. For the 9th digit, also add floor(d[9] * 5 / 10) to the total sum.
- 3. Sum all weighted products into total S.
- 4. Compute remainder of S modulo 10.
- 5. Check digit = (10 - remainder) mod 10. BRN is valid if it matches digit 10.