Last Updated: April 2026
South Korea has emerged as a major expat destination β particularly in Seoul's finance and technology sectors β and its tax system offers a genuinely useful concession for foreign workers: the option to be taxed at a flat 19% national rate rather than progressive rates reaching 45%. For expats on higher salaries, this flat rate election can save tens of thousands of dollars annually compared to the standard progressive system.
This guide explains South Korea's tax structure for expats in 2026: how the progressive and flat rate systems compare, social insurance obligations, how residency is determined, and what US citizens living in South Korea need to file.
According to the National Tax Service (NTS), South Korea's national income tax uses eight progressive brackets:
| Taxable Income (KRW) | National Tax Rate |
|---|---|
| Up to 14,000,000 | 6% |
| 14,000,001β50,000,000 | 15% |
| 50,000,001β88,000,000 | 24% |
| 88,000,001β150,000,000 | 35% |
| 150,000,001β300,000,000 | 38% |
| 300,000,001β500,000,000 | 40% |
| 500,000,001β1,000,000,000 | 42% |
| Above 1,000,000,000 | 45% |
On top of national income tax, a local income tax (LIT) surcharge of 10% is applied β so the combined effective rates are 6.6% to 49.5%. At an income of 100,000,000 KRW (approximately $75,000 USD), the combined effective rate is approximately 25β28% after standard deductions.
South Korea provides a significant benefit for qualifying foreign workers: the ability to elect a single flat tax rate of 19% on Korean-source employment income, rather than the progressive rates. With the 10% local income tax surcharge, the combined flat rate is 20.9%.
The flat tax election is available to foreigners who work in Korea under certain employment visa categories, including:
The flat rate election was available for 5 years originally, but has been extended to 20 years of continuous Korean tax residency. This is a substantial concession that differentiates Korea from many competing jurisdictions.
The flat rate (20.9% combined) is generally better than progressive rates for expats earning above approximately 70,000,000β80,000,000 KRW per year (~$53,000β60,000 USD). Below that income level, the progressive rates with standard deductions may produce a lower effective rate.
Key trade-off: under the flat rate, you cannot claim most standard deductions (earned income deduction, dependent deductions, education expenses, etc.). These deductions can significantly reduce progressive-rate liability at lower incomes.
South Korea has four mandatory social insurance schemes. Employee contributions in 2026 are approximately:
| Scheme | Employee Rate | Employer Rate |
|---|---|---|
| National Pension (NPS) | 4.5% | 4.5% |
| National Health Insurance (NHIS) | 3.545% | 3.545% |
| Employment Insurance | 0.9% | 1.15β1.75% |
| Industrial Accident (Workers' Comp) | 0% | Sector-based |
Total employee contribution: approximately 8.945% of gross salary.
From 2019, all registered foreign residents in Korea must enrol in the National Health Insurance Service (NHIS) β previously many expats maintained private insurance only. The NHIS covers a broad range of medical services at subsidised rates. The contribution is the same as Korean nationals: 3.545% employee, 3.545% employer.
Korea has pension totalization agreements with many countries (including the US), meaning expats may avoid double pension contributions. Under the Korea-US totalization agreement, workers covered by US Social Security continue paying US Social Security tax rather than the Korean National Pension. Confirm your specific situation with payroll or a tax adviser.
South Korea determines tax residency on two criteria:
Korean tax residents are taxed on worldwide income. Non-residents are taxed only on Korean-source income, at withholding rates (typically 20% for employment income, 22% with local surcharge).
If you arrive or depart Korea mid-year, you are treated as a resident for the portion of the year you spend in Korea (provided you meet the 183-day threshold). Employment income earned before arrival or after departure is not subject to Korean income tax.
When departing Korea permanently, you should: file a final income tax return, close any Korean bank accounts or report foreign assets, and deregister from the Alien Registration system. Failure to close out properly can create complications when re-entering Korea on a future visa.
Korean income tax returns are filed annually with the National Tax Service. Employees have tax withheld at source (year-end settlement is performed in January for the prior year). The formal filing deadline is May 31.
Unlike many countries, Korea conducts a detailed year-end settlement process in January through the employer for salaried employees. Your employer collects documentation for deductions and credits, calculates the final liability, and adjusts your February payslip accordingly. Most employees do not need to file a separate return if their only income is employment income and the year-end settlement was completed correctly.
Situations requiring a personal return (5μ μ’ ν©μλμΈ μ κ³ , May general income tax filing):
US citizens in South Korea must file US federal tax returns annually in addition to Korean obligations.
See FEIE vs Foreign Tax Credit for the analysis most relevant to your situation.
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Transfer Money From South Korea βForeign workers in South Korea can elect a flat national income tax rate of 19% instead of the progressive rates (6%β45%). Adding the 10% local income tax surcharge, the total combined rate is 20.9%. The election is available for up to 20 years of Korean tax residency. The downside: you cannot claim most standard deductions under the flat rate. The flat rate is generally beneficial for expats earning above approximately 70β80 million KRW per year.
South Korea imposes a local income tax (LIT) of 10% on your national income tax liability. This is not 10% of income β it is 10% of the tax calculated. So if your national income tax is 5,000,000 KRW, the local income tax adds 500,000 KRW, for a total of 5,500,000 KRW. This applies to both the progressive rates and the flat tax election.
Yes. Since 2019, all registered foreign residents in South Korea must enrol in the National Health Insurance Service (NHIS). Contributions are 3.545% of gross salary (employee) with an equal employer contribution. NHIS provides broad coverage for medical services at subsidised rates. You cannot opt out in favour of private insurance only.
You become a South Korean tax resident if you spend 183 or more days in Korea in a calendar year, or if you maintain a permanent domicile (home or primary base of life) in Korea. Korean tax residents pay tax on worldwide income. Non-residents pay only on Korean-source income at withholding rates.
Korea's year-end settlement (yeonmal jeongsan) is a January process where employers recalculate each employee's annual tax liability using actual deduction documentation β dependents, education costs, medical expenses, insurance premiums, and more. The difference from withheld tax is refunded or collected via the February payslip. Most salaried employees with only employment income do not need to file a separate annual return after this process.
Generally yes. The Korea-US Totalization Agreement means US citizens employed in Korea typically remain under US Social Security coverage and are exempt from Korean National Pension contributions. Your employer must obtain a Certificate of Coverage from the US Social Security Administration to confirm this. Do not assume exemption without documentation β the default without a certificate is that Korean NPS contributions apply.
The formal income tax filing deadline in South Korea is May 31 for the previous calendar year's income. However, salaried employees whose year-end settlement (μ°λ§μ μ°) was correctly completed by their employer typically do not need to file a separate return. Those with additional income sources (freelance, rental, foreign income) must file by May 31 using the NTS online system (Hometax) or through a tax agent.