South Korea Tax ID Number (TIN) Guide 

Introduction

A Tax Identification Number (TIN) is a unique identifier used by tax authorities to track an individual or business’s tax obligations and ensure compliance with the country’s tax laws. In South Korea, the TIN is essential for individuals, businesses, and legal entities when fulfilling tax-related responsibilities. This guide offers precise, verified information regarding TINs in South Korea, sourced directly from official government and tax authority resources. 

Tax Identification Number Types 

In South Korea, the primary TIN used for individuals and businesses is the Resident Registration Number (RRN) for individuals and the Business Registration Number (BRN) for businesses. 

• Resident Registration Number (RRN): 

• The RRN is issued to all South Korean citizens and resident foreigners for identification and tax purposes. 

• This number serves as the TIN for individuals who are required to file taxes, such as those employed or self-employed. 

• Business Registration Number (BRN): 

• This TIN is issued to businesses and legal entities operating in South Korea. The BRN is necessary for companies to meet tax obligations, including VAT, income tax, and corporate tax filings. 

Both numbers are critical for ensuring the accurate filing and payment of taxes, and their use extends beyond just tax purposes to areas like opening a bank account or applying for various government services. 

TIN Format and Structure 

Each TIN used in South Korea follows a specific format: 

• Resident Registration Number (RRN): 

• The RRN consists of 13 digits in total. 

• The format is as follows: YYYYMMDD-XXXXXXX. 

• The first part (YYYYMMDD) indicates the individual’s date of birth. 

• The second part (XXXXXXX) is a unique identifier, where the first digit indicates gender and the remaining digits are a serial number used to distinguish between individuals. 

Example: 870405-1234567 (This is a sample format for illustration purposes). 

• Business Registration Number (BRN): 

• The BRN is 10 digits long. 

• The format is as follows: XXX-XX-XXXXXX. 

• The first three digits represent the business classification, the middle two digits represent the administrative region code, and the last five digits are a unique identifier for the business. 

Example: 123-45-678901 (This is a sample format for illustration purposes). 

Each number is unique to the individual or entity and is used in all tax-related interactions. 

Issuing Authority and Registration Process 

The National Tax Service (NTS) of South Korea is the official authority responsible for issuing TINs, including the Resident Registration Number (RRN) and the Business Registration Number (BRN). 

• Official Name of Issuing Body: National Tax Service (NTS) 

• Official Website: www.nts.go.kr 

TIN Registration Process 

1. Eligibility: 

• Individual TIN (RRN): All South Korean citizens and registered foreign residents are eligible for the RRN. It is automatically assigned to citizens at birth or when they register with local authorities. 

• Business TIN (BRN): Businesses must apply for the BRN when registering their business with the NTS or the local tax office. 

2. Documents Required: 

• For Individuals: Proof of identity (e.g., national ID card or passport). 

• For Businesses: Business registration documents, including the business plan, registration with the Ministry of Trade, Industry, and Energy (MOTIE), and the Articles of Incorporation for companies. 

3. Application Process: 

• For Individuals: South Korean citizens automatically receive an RRN at birth. Foreign residents must register with the Seoul Immigration Office or other local authorities. 

• For Businesses: Businesses must submit an application form to the National Tax Service or the local tax office. This can be done online via the NTS website or in person at local tax offices. 

• Fees: The registration of the Business Registration Number is generally free, although certain administrative fees may apply in specific cases. 

For the latest details on the application process and fees, businesses should consult the official National Tax Service website. 

TIN Verification and Lookup 

To verify a TIN in South Korea, both individuals and businesses can use the official National Tax Service (NTS) portals. 

• TIN Verification for Individuals: 

• Individuals can verify their Resident Registration Number (RRN) by contacting the Seoul Immigration Office or local government offices. 

• TIN Verification for Businesses: 

• Businesses can verify their Business Registration Number (BRN) by visiting the official NTS Business Registration Verification page. 

Official Portal: www.nts.go.kr 

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TIN and VAT Number Connection 

In South Korea, the Business Registration Number (BRN) doubles as the VAT number for businesses. Businesses that are subject to VAT must use their BRN for VAT reporting and filings with the National Tax Service. 

• VAT Number Format: The VAT number is the same as the Business Registration Number (BRN). 

It is important for businesses to ensure they have a valid BRN to comply with VAT and other tax regulations. If businesses are unsure, they can verify their BRN through the official verification tool. 

Importance of Accurate TIN Validation 

The correct and validated TIN is essential for both individuals and businesses in South Korea. An incorrect or invalid TIN can lead to serious consequences, including: 

• Delays in Tax Filings: Incorrect TINs can cause delays in processing tax returns, which can lead to penalties or missed deadlines. 

• Audit Risks: Errors in TIN validation can increase the risk of tax audits or investigations from the National Tax Service. 

• Penalties and Fines: Incorrect TINs can result in fines or penalties due to non-compliance with tax laws. 

Validating your TIN ensures that your tax records are accurate and helps maintain compliance with South Korea’s tax system. 

Why Accurate TIN Validation Matters

Ensuring the accuracy of your TIN is critical for both businesses and individuals in South Korea. An incorrect or unverified TIN can lead to serious complications such as:

• Delays in tax processing
• Rejection of tax exemption claims
• Fines and penalties for non-compliance
• Rejection of e-invoicing submissions
• Onboarding unqualified suppliers or customers
• Data quality issues across finance and compliance systems

Using the South Korea National Tax Service’s official website or TaxDo’s real-time global tax ID verification platform ensures accurate Tax ID validation, error reduction, and full compliance with South Korean tax laws.

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