Korea TIN number guide
Resident Registration Number
The Resident Registration Number (RRN) in South Korea is issued by the Ministry of Interior to Korean citizens residing in the country. This unique identifier plays a pivotal role when a corporation withholds taxes from its employees' wages and salaries or when an individual files tax returns for income, transfer, inheritance, and/or gift.
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| Resident Registration Card |
Additionally, for the purpose of Common Reporting Standard (CRS) reporting, the Passport Number, as issued by the Ministry of Foreign Affairs, is accepted as an alternative TIN.
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| Koeran Passport |
Format
The Resident Registration Number, structured as 13 digits (XXXXXX-XXXXXXX), is assigned with specific criteria in mind:
(a) The first six digits are derived from an individual's date of birth. For instance, someone born on January 2, 1985, would have the initial six digits as 850102.
(b) 7th digit serves to identify the gender of individuals.
Business Registration Number
Issued by the head of a district tax office in the relevant jurisdiction, a Business Registration Number is a crucial identifier for entities starting a business in South Korea. This unique number serves as the Tax Identification Number (TIN) for all tax-related filings, including corporate tax returns.
Format
- Comprising 10 digits.
- TIN structure: XXX-XX-XXXXX.
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| Business Registration Certificate |
Corporation Registration Number
In the case of a legal entity that has registered its foundation with the court, it receives a Corporation Registration Number managed by the court. Notably, this Corporation Registration Number is also recognized and accepted as the TIN for the entity in specific situations.
Format
- Consisting of 13 digits.
- TIN structure: XXXXXX-XXXXXXX.
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| Certified Copy of the Corporation Registry |
Frequently Asked Questions
Can a Korean business legally collect my RRN (주민등록번호) for a routine commercial transaction?
No. Since August 2014, the Personal Information Protection Act (PIPA) prohibits any person or entity from collecting or processing a Resident Registration Number (RRN) without an explicit legal basis — consent alone is not sufficient. [1] Unauthorized collection carries a fine of up to KRW 30 million; failure to protect an RRN that was lawfully collected exposes the processor to a fine of up to KRW 500 million. Under 2026 PIPA amendments, repeat or large-scale violations now attract administrative fines of up to 10% of total annual revenue. [2] Businesses must instead use surrogate identification methods (IPIN, mobile verification, or digital certificate) for online identity checks. If a commercial vendor demands your RRN for a purpose with no statutory basis — such as a loyalty programme sign-up — you may refuse and file a complaint with the Personal Information Protection Commission (PIPC).
What is the difference between a Business Registration Number (BRN) and a Corporation Registration Number (CRN), and which one must appear on a Korean tax invoice?
These are two separate identifiers issued by different authorities. The Business Registration Number (사업자등록번호) is a 10-digit number (XXX-XX-XXXXX) issued by the district tax office under the NTS — it is the primary tax identifier for all VAT, corporate tax, and withholding filings. [3] The Corporation Registration Number (법인등록번호) is a 13-digit number (XXXXXX-XXXXXXX) issued by the court registry when a legal entity is incorporated; it proves legal existence and is accepted as a TIN in CRS/FATCA contexts, but it is not a tax invoice field. On Korean electronic tax invoices (전자세금계산서) and all NTS filings, only the BRN is valid. Entering only the CRN is a common error among newly incorporated foreign subsidiaries and will cause the recipient's input VAT claim to be rejected. Always obtain the BRN from the NTS-issued Business Registration Certificate (사업자등록증), not from the court registry extract. [3]
I run a foreign SaaS business with no Korean entity. Do I need to register for Korean VAT before my first B2C sale?
Yes — Korea applies a zero-threshold rule for non-resident digital service providers. There is no minimum turnover exemption: registration via the NTS Hometax "Simplified Business Operator" scheme (간편사업자 등록) is mandatory before the first B2C sale of electronic services (software, cloud, streaming, online advertising) to a Korean consumer. [4] Once registered, you charge 10% VAT and file quarterly returns by the 25th of the month following each quarter. A penalty of 1% of total supply value applies for failure to register on time, accruing up to the day simplified registration is completed — meaning a foreign provider who has been selling to Korean consumers for two years without registration faces significant back-penalties on top of uncollected VAT. [4] B2B supplies where the Korean business self-accounts under reverse charge do not require the foreign supplier to register, but you must verify the buyer's BRN to confirm B2B status. Note that from 1 July 2025, foreign digital intermediary platforms must also submit quarterly transaction-detail reports to the NTS under Article 75 of the VAT Law.
My Korean sole proprietorship just crossed KRW 80 million in annual sales. Must I now issue electronic tax invoices, and what are the penalties for missing the transmission deadline?
Yes. Since July 2024, sole proprietors (개인사업자) whose previous-year supply value reached KRW 80 million or more must issue electronic tax invoices (전자세금계산서) for all VAT-liable supplies, regardless of whether they are general or simplified VAT taxpayers. [5] This threshold was progressively lowered from KRW 300 million to KRW 100 million (July 2023) and then to KRW 80 million (July 2024), so businesses that were exempt two years ago may be non-compliant today without realising it. Corporations have been subject to mandatory e-invoicing since 2011. Invoices must be transmitted to the NTS via Hometax on the day of issuance; a monthly bulk submission by the 10th of the following month is the absolute latest. Penalties are graduated: 2% of supply value for failing to issue any invoice; 1% of supply value for issuing on paper or failing to transmit to the NTS by the 10th. [4] Pre-enrol in the Hometax e-invoicing module before the obligation activates — enrolment takes several working days.
As a foreign employee in Korea, should I elect the 19% flat income tax rate during year-end settlement (연말정산), or use the progressive tax rates?
Foreign workers who began employment in Korea by 31 December 2026 may elect a flat income tax rate of 19% (plus 1.9% local income tax) on employment income in lieu of the standard progressive rates of 6%–45%. [6] The critical trade-off: electing the flat rate forfeits all other income deductions, tax exemptions, and tax credits — including the earned income deduction, dependent deductions, and insurance premium credits that Korean taxpayers use to reduce their effective rate. The flat rate is advantageous primarily for high earners whose marginal progressive rate exceeds 19%, and it is unavailable if the employee works for a related-party company (as defined by the tax authority). [6] The election must be submitted to the employer at the time of year-end settlement or to the NTS at annual return filing; the NTS publishes a multilingual Year-End Tax Settlement guide (available in English, Chinese, and Vietnamese) for foreign residents each January.
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