2026 Capital Gains Tax: Who Counts as a Non-Resident?

Staying abroad for more than 183 days does not automatically grant 'non-resident' status for tax purposes. From 2026, this standard will become even stricter. Even if an individual resides in Korea for 183 days or more across two tax periods, they will be classified as a resident, and crucially, the substantive criterion of 'livelihood base' will act as a key variable. Depending on whether one is a resident or non-resident, the tax on selling the same home can vary by nearly 59 times, ranging from approximately KRW 4.8 million to KRW 280 million. This article summarizes essential information for property owners planning overseas assignments, studies, or emigration.

Simple Date Counting Is Over: What Changes in 2026?

The existing Income Tax Act defined a resident as 'an individual with a domicile in Korea or a place of abode in Korea for 183 days or more.' Here, 183 days were calculated within a single tax period (January 1 to December 31). This allowed for strategies where individuals maintained fewer than 183 days of domestic stay in each tax period by departing at the end of the year and returning early the next year.

From January 1, 2026, this formula will change. According to the revised Income Tax Act, an individual will also be deemed a resident if they continuously maintain a place of abode in Korea for 183 days or more across two tax periods. For example, if someone stays in Korea continuously for eight months from October 2026 to May 2027, they will be considered a resident because their combined stay exceeds 183 days, even if the stay in each calendar year is less than 183 days.

The core of this change signals that tax authorities will look more deeply into the substance rather than merely formal requirements. This clearly intends to block strategic entry and exit management for tax avoidance purposes and reinforce the principle of taxation based on substance.

How Is 'Livelihood Base' Determined?

As important as the 183-day rule is the determination of 'domicile.' According to Article 2 of the Enforcement Decree of the Income Tax Act, domicile is not based on registered residency but is determined by "objective facts of living relations, such as the presence of family members living together in Korea and assets located in Korea." If an individual is determined to have a domicile in Korea, they become a resident regardless of their period of stay abroad.

Specifically, the factors considered by tax authorities include:

Article 2, Paragraph 3 of the Enforcement Decree of the Income Tax Act stipulates that an individual engaged in an "occupation that typically requires continuous residence in Korea for 183 days or more" is considered to have a domicile in Korea. Furthermore, Paragraph 4 of the same article states that an individual is also deemed to have a domicile if "family members living together are in Korea, and, considering their occupation and asset status, it is recognized that they will reside in Korea for 183 days or more."

Conversely, an individual holding foreign nationality or permanent residency, who has no family members living together in Korea, and whose re-entry and residence in Korea are not recognized based on their occupation and asset status, is considered not to have a domicile in Korea.

For instance, if an individual has been working at a US branch for two years, but their spouse and children reside in Seoul, with children attending domestic schools, and they own an apartment in Seoul, it is highly likely that their 'livelihood base' will be deemed to be in Korea. On the other hand, if the entire family has moved to the US, attending local schools and jobs, has disposed of domestic real estate, and has acquired permanent residency, there is a greater chance of being recognized as a non-resident.

Resident vs. Non-Resident: Critical Differences in Capital Gains Tax

The distinction between a resident and a non-resident is particularly crucial for real estate capital gains tax for three reasons.

First, eligibility for the one-household one-home tax exemption. According to Article 89 of the Income Tax Act, if a resident family owns one home for two years or more (with an additional two-year residency requirement for properties in designated speculative areas) and sells it, capital gains tax is exempt up to a sale price of KRW 1.2 billion. This is the most powerful benefit for real estate tax savings. Non-residents are generally not eligible for this tax exemption.

However, there is an important exception. If an individual departs due to reasons such as school enrollment, employment, or overseas emigration, and sells the home within two years from the date of departure, they may still be eligible for the one-household one-home tax exemption. This two-year period is effectively the only window of opportunity for non-residents.

Second, differences in long-term special deduction rates. A resident who owns and resides in a one-household one-home for 10 years or more can receive a deduction of up to 80% of the capital gains (40% for holding period + 40% for residency period). In contrast, non-residents are only subject to the general long-term special deduction, receiving a maximum of 30% even after holding for 10 years or more. This means the deduction rate differs by 2.7 times, from 80% to 30%, for the same holding period.

Third, exclusion from tax reductions under the Restriction of Special Taxation Act. Non-residents, except in specific cases, are not eligible for various tax reduction provisions under the Restriction of Special Taxation Act, which limits additional tax-saving options.

Tax Differences in Numbers: Resident vs. Non-Resident Simulation

Let's calculate the difference with a specific example.

Assume Mr. A acquired an apartment in Seoul for KRW 500 million, held and resided in it for 10 years, and then sold it for KRW 1.5 billion. The capital gain is KRW 1 billion.

For a resident (one-household one-home), since capital gains up to KRW 1.2 billion are exempt, only the capital gain corresponding to the excess amount of KRW 300 million (3/15 = 20% of the total gain), which is KRW 200 million, is subject to tax. Applying the long-term special deduction of 80% (40% for 10-year holding + 40% for 10-year residency), the actual taxable base is approximately KRW 37.5 million (after deducting the basic deduction of KRW 2.5 million). The capital gains tax on this would be approximately KRW 4.37 million, totaling approximately KRW 4.8 million including local income tax.

For a non-resident, the one-household one-home tax exemption does not apply, so the entire capital gain of KRW 1 billion is subject to tax. The long-term special deduction applies only at the general maximum of 30%, resulting in a taxable capital gain of KRW 700 million. After the basic deduction, the taxable base is approximately KRW 697.5 million. Applying progressive tax rates (6-42%), the calculated tax is approximately KRW 257 million, totaling approximately KRW 283 million including local income tax.

For the same home and the same sale price, the tax differs by approximately 59 times, from KRW 4.8 million to KRW 283 million, depending on the tax status. This means that the 'livelihood base' criterion is worth hundreds of millions of won.

Historical Context: Why Are Standards Being Tightened Now?

The reinforcement of resident determination criteria is an extension of the government's policy to refine real estate taxation. The government has repeatedly introduced measures like heavy capital gains tax on multiple homeowners to curb real estate speculation but has repeatedly suspended and supplemented them based on market conditions.

With the expiration of the heavy capital gains tax suspension for multiple homeowners in May 2025, the overall real estate tax system is shifting towards a stricter stance. This move aims to block even the workaround of converting to non-resident status through overseas stays. As cross-border human exchanges become more active, taxation based on substantive livelihood rather than formal entry/exit records is also an international trend.

The OECD Model Tax Convention also stipulates that in determining dual residency, the order of judgment is 'permanent home → center of vital interests → habitual abode → nationality,' aligning with the international standard of judging based on the substantive livelihood base.

Dual Resident Issues: Which Country's Tax Law Applies?

It is possible for individuals staying abroad to be deemed residents in both Korea and their country of stay. In such cases, the 'tie-breaker rule' of the tax treaty between the two countries applies.

According to the OECD Model Tax Convention, the order of determination is as follows:

Since most tax treaties concluded by Korea follow this structure, it is important for individuals staying abroad to review in advance at which priority their situation will be determined.

How to Prepare for Disputes with Tax Authorities

Since the 'livelihood base' criterion relies on a comprehensive judgment, the possibility of disputes between taxpayers and tax authorities increases. The key to preparation is systematically organizing objective documentary evidence.

To prove non-resident status, the following documents are needed:

Conversely, if one wishes to be recognized as a resident (for the one-household one-home tax exemption), one should prepare evidence such as facts of domestic family cohabitation, maintenance of domestic National Health Insurance and National Pension, status of domestic asset ownership, and dispatch orders showing that overseas stay was a temporary assignment.

The key is to support 'where your primary base of life is' with consistent and specific evidence. This evidence should be prepared from the time overseas stay begins, not just at the time of sale.

Outlook and Implications

The 2026 rule, which combines two tax periods for the 183-day calculation, will effectively block strategies of splitting tax periods to create non-resident status. Coupled with the 'livelihood base'-centric domicile determination, it will become difficult to maintain non-resident status for tax purposes merely by managing entry/exit dates.

Individuals planning overseas stays and domestic property sales should first check the possibility of utilizing the tax exemption exception of selling within two years of departure. If conditions for school enrollment, employment, or overseas emigration are met, completing the sale within this period is the most reliable tax-saving path.

If the two-year period is exceeded, one must coolly assess where their actual livelihood base lies and calculate whether resident or non-resident status is more advantageous. Given the power of the one-household one-home tax exemption and the 80% long-term special deduction, being classified as a resident is often overwhelmingly more beneficial.

As uncertainty has increased, it is wise to consult a tax expert experienced in international taxation to review all scenarios before making major decisions such as property sales.