Korean Business Registration Number Validator — 10-Digit Checksum
DeveloperA Korean business registration number validator checks whether a 10-digit Korean business number has the correct numeric format and checksum.
Important basis and limitations
- Basis date
- Content basis date: 2026-07-07
- Scope
- General cases under Korean criteria
Reference sources
This is a reference calculation from public sources and your inputs. It may not reflect personal circumstances, recent changes, or an authority’s interpretation. Confirm with an official source or qualified professional before filing, contracting, clinical care, contraception, or another important decision.
What is it
A Korean business registration number has 10 digits, and the last digit must match a checksum calculated from the first nine digits. This tool applies the commonly used checksum algorithm to catch typos and formatting errors. A valid checksum does not prove that the business exists, identify the owner, or show active/closed status. For official status, use the National Tax Service Hometax lookup.
How to use
- 1Enter the 10-digit number. Hyphens are ignored.
- 2Press validate to check numeric format and checksum.
- 3Use Hometax official lookup when you need real business status.
Reference
| Example | Result |
|---|---|
| 220-81-62517 | Checksum valid |
| 123-45-67890 | Checksum invalid |
| Fewer than 10 digits | Format invalid |
Sources & standards
- National Tax Service Hometax business registration status service - National Tax Service
- MDN Web Docs: Client-side web APIs - MDN Web Docs
FAQ
Does a valid checksum prove the business exists?
No. A checksum only catches format errors. Use the official NTS Hometax service to verify registration or active/closed status.
Can this tool generate business registration numbers?
No. It only validates input and does not provide number generation.
Is the business number sent to a server?
No. Validation runs entirely in your browser and the input is not sent or stored.