Korea Resident vs Non-Resident Tax: The 183-Day Test and What You Pay

What makes you a resident or non-resident

Korea’s Income Tax Act (Article 1-2) measures residence with a time threshold: a resident is any individual who has a domicile or place of residence in Korea for at least 183 days in a tax period. Everyone else is a non-resident.

The tax authorities decide the ‘place of residence’ from the objective facts of your life here — where your family lives, your assets, the centre of your economic activity. If the job you hold requires you to live in Korea for 183 days or more, a domicile is presumed to exist.

Once your stay passes the 183-day mark, you are treated as a resident for that tax year. This decides which income Korea has the right to tax.

What residents pay tax on

Article 3(1) of the Income Tax Act taxes residents on all income in the Act — that is, worldwide income. Your overseas salary, dividends and rental income are reportable here on top of your Korean income.

There is an important carve-out in the same clause for foreign residents: if you are a foreign national resident who has lived in Korea for 5 years or less, combined, in the 10 years before the end of the tax period, income from outside Korea is taxed only to the extent it is paid or remitted into Korea. In practice many newer foreign residents are not taxed on overseas income that never enters Korea. The remittance basis and the foreign tax credit are covered in detail in our South Korea foreign income tax guide.

Residents file a global income tax return by the end of May of the following year. If your employer withholds through the year-end settlement, the return reconciles the difference.

What non-residents pay tax on

Non-residents are taxed only on Korean-source income under Article 119 of the Act. That list includes Korean-source employment income, business income, dividends and interest paid by a Korean entity, and income from real estate or assets located in Korea.

Because their tax liability is narrower, non-residents typically have tax withheld at source by the payer and file a less involved return than residents. The practical question for most expats is not ‘resident or non-resident’ on paper — it is whether their stay has already crossed the 183-day threshold and therefore shifted them into worldwide taxation.

Global vs separate taxation

Residents bring their individual income types together into a single global (aggregate) income — employment, business, rental and interest income are summed and then taxed at progressive rates (Article 4).

Some incomes are instead taxed separately: certain financial income, retirement income and capital gains are excluded from the aggregate base and taxed at their own rates or withheld at source (Article 14(3)). The difference matters for planning, because income that is taxed separately is not pulled into the higher brackets of your global income.

The 19% flat rate for foreign workers

Under the Special Tax Treatment Control Act (Article 18-2), a foreign employee (other than a day worker) may choose a flat 19% income tax rate instead of the progressive 6–45% brackets. The choice applies to employment income for 20 years from the start of employment — the so-called ‘5-year rule’ is outdated; it was extended to 20 years for income arising from 1 January 2023.

There is a start-date cutoff. The statute applies to foreign employees who first begin working in Korea on or before 31 December 2026. If you start after that date, the treatment does not apply unless the law is extended again — it has been extended repeatedly, but do not assume it. There is also an exclusion for employees of certain related-party companies.

Note that this flat rate has nothing to do with the 183-day test. It is an opt-in for foreign employees regardless of residency, and the choice is made by the employer’s year-end settlement or by the employee when filing. Comparing the two routes needs an estimate of your income level, because the flat rate can cost you more than the brackets at low incomes. For a fuller comparison of the flat rate against the progressive brackets, see the 19% flat tax guide.

What to check before filing

Before you file in Korea, decide which of the three situations describes you:

1. Resident under 183 days — keep track of entry-exit dates, because the count is done in days per tax period
2. Resident past 5 years — overseas income becomes fully taxable, remittance or not
3. Foreign worker using the 19% flat rate — confirm whether your employer applied it in the year-end settlement

Keep proof of days in Korea (boarding record, flights), and if you plan to use the remittance carve-out, retain evidence of what was paid or remitted into Korea. Tax rules change, so confirm the current figures with the National Tax Service before filing.