Home Business Registration Number South Korea
South Korea Business Registration Number validator
How the Business Registration Number format works
- Format
- 10 digits: 3-digit tax office code + 2-digit business-type code + 4-digit serial number + 1 weighted check digit
- Example
- 1248100998
Things to watch for
- This is a business entity number (사업자등록번호), issued to companies and sole proprietors — not a personal Resident Registration Number
- Often written with hyphens as XXX-XX-XXXXX; strip them before checking the raw digits
- Checksum only — a pass confirms the number is internally consistent, not that the business is currently registered or active with the NTS
^[0-9]{10}$A Business Registration Number (사업자등록번호, BRN) is the 10-digit identifier South Korea’s National Tax Service (NTS) issues to every company and sole proprietor operating in the country — usually printed on invoices, tax receipts, and business registration certificates as three groups separated by hyphens, like 124-81-00998. It’s a business-facing tax ID, not a personal one: it’s entirely separate from the Resident Registration Number every Korean citizen and resident carries, which identifies people rather than businesses and follows its own, different checksum rules.
How the digits are structured
The first 3 digits identify the tax office that issued the number. The next 2 digits classify the kind of business the number belongs to — different ranges cover corporations, individual proprietors, and other entity types. A 4-digit serial number follows, and the final digit is a weighted check digit calculated from the nine digits before it, which is what this tool recomputes and compares.
How this validator works
This tool accepts the number with or without the standard hyphens — separators are stripped automatically — confirms 10 digits remain, then runs the weighted check-digit formula the NTS uses to generate valid BRNs, entirely client-side in your browser with nothing sent to a server.
What a pass doesn’t tell you
A pass confirms the 10 digits are internally consistent — not that the business is currently registered, active, or in good standing with the NTS.
Scope: this page and tool cover South Korean BRN format and checksum validation only — not live business-registration status.
Content last reviewed 2026-08-09.
Business Registration Number FAQ
Is a Business Registration Number the same as a Korean citizen's personal ID?
No. The Business Registration Number (사업자등록번호) is issued by the National Tax Service to companies and sole proprietors — it's completely separate from a person's 13-digit Resident Registration Number (주민등록번호), which uses a different check-digit formula and is far more sensitive personal data.
What do the middle digits of a Korean BRN mean?
The first 3 digits identify the tax office that issued the number, and the next 2 classify the type of business or taxpayer it belongs to. Only the final digit is the check digit this tool verifies against the other nine.
Does a valid checksum confirm the business is still registered?
No. It only confirms the 10 digits are mathematically consistent with the check-digit formula — not that the business is currently active with the National Tax Service.