- The 10-digit business registration number comes from the tax office, not the court.
- Apply within 20 days of starting business; it usually takes a few business days.
- The middle two digits show the type of business — 81, 86, 87, 88 for corporate head offices.
- The last digit is a check digit, so typos can be caught instantly.
A Korean company has two numbers. The court registry gives it a 13-digit corporate registration number when it is incorporated. The tax office gives it a 10-digit business registration number when it registers for tax. The second one is the one you will write a hundred times a month.
| Corporate registration number | Business registration number | |
|---|---|---|
| Issued by | District court registry | National Tax Service |
| Format | 13 digits | 10 digits: 000-00-00000 |
| Used for | Legal identity | Invoices, VAT, banks, contracts |
Getting one
After incorporation, the company applies to the local tax office with its registry extract, articles, lease and shareholder register — plus the foreign investment registration certificate if it has FDI status. The law gives 20 days from the start of business; in practice we file right after incorporation, because the bank and invoicing need the number.
Reading one
The format is XXX-XX-XXXXX. The first three digits identify the tax office; the middle two the type of taxpayer; the next four are a serial number; the last is a check digit calculated from the other nine.
Ten digits, two hyphens — and every Korean invoice asks for them.
Checking a counterparty
A valid format does not prove a business is active. Whether a number is open, suspended or closed — and whether the business is a general or simplified VAT taxpayer — is confirmed through the National Tax Service’s Hometax service. Do it before you pay a new supplier’s first invoice.
Questions readers ask
What is a Korean business registration number?
A 10-digit tax identification number (사업자등록번호) issued by the National Tax Service, formatted 000-00-00000.
How long does it take to get one?
Usually a few business days after application.
What do the middle two digits mean?
The type of taxpayer: for example 81, 86, 87 and 88 for corporate head offices and 85 for branches.
How do I check if a Korean business is active?
Through the National Tax Service’s Hometax business status lookup.