If you are a tax resident of Korea and you sell US stocks — Apple, Tesla, an S&P 500 ETF in your Schwab or Interactive Brokers account — Korea taxes that gain as overseas (foreign) capital gains at a flat 22% (20% national + 2% local) on the amount above the annual 2.5 million KRW basic deduction. This Korea capital gains tax on US stocks calculator for residents does the part everyone gets wrong: it computes your gain in won using the correct exchange rate on the buy date and the sell date, applies the 2.5M deduction, and gives your exact 22% bill. The FX-cost-basis angle is the moat — a dollars-only number is simply wrong for a Korean return.
Enter your purchase and sale amounts (in USD) with the FX rate on each date, and the calculator returns your KRW-denominated gain, the taxable amount after the 2.5M deduction, and your 22% tax.
Korean tax residents are taxed on their worldwide income, and gains on foreign securities — including US-listed shares and ETFs — fall under overseas capital gains. The rate is a flat 22% (a 20% national capital-gains tax plus a 2% local surtax) on net gains above a 2.5 million KRW annual basic deduction. Unlike Korean-listed shares, where small retail investors are largely exempt, gains on US stock are squarely taxable for residents, and the responsibility to report is on you — your US broker does not withhold Korean tax.
This is the single most important — and most misunderstood — feature. Korea measures your gain in won, not dollars. Your cost basis is the purchase price converted at the exchange rate on the buy date, and your proceeds are the sale price converted at the rate on the sell date. Because the won/dollar rate moves, your Korean taxable gain can differ sharply from the gain your brokerage shows in dollars. A stock that rose in dollars can produce a smaller — or larger — gain in won depending on whether the dollar strengthened or weakened between your two trades.
You buy $10,000 of a US ETF when the rate is 1,300 KRW/USD, and sell for $15,000 when the rate is 1,400 KRW/USD:
| Step | USD | FX | KRW |
|---|---|---|---|
| Cost basis | $10,000 | 1,300 | 13,000,000 |
| Sale proceeds | $15,000 | 1,400 | 21,000,000 |
| Gain (won) | $5,000 | — | 8,000,000 |
| − basic deduction | — | — | 2,500,000 |
| Taxable | — | — | 5,500,000 |
| Tax at 22% | — | — | 1,210,000 |
Your dollar gain was $5,000, but the weaker won at sale time inflated the won gain to 8,000,000 KRW, raising the Korean tax. Had the won strengthened instead, your taxable won gain would have been smaller than the dollar gain suggested. This is exactly why a dollars-only mental calculation is unreliable for a Korean return.
Every resident gets a 2.5 million KRW basic deduction against total overseas capital gains per year — not per trade. If you sell several foreign positions in the same year, you pool all the gains, subtract a single 2.5M deduction, and apply 22% to the remainder. The calculator lets you enter other gains already realized so it shares the deduction correctly and shows the tax attributable to the specific sale you are modelling.
Overseas capital losses can offset overseas capital gains in the same tax year, so if one US position lost money while another gained, you are taxed only on the net. However, Korea generally does not let you carry a net overseas capital loss forward to future years, so unused losses are lost when the year closes. Harvesting losses in the same year as your gains is therefore the practical way to reduce the bill.
Overseas capital gains are reported in your annual global income / capital gains return filed in May of the year after the sale (so 2026 sales are reported in May 2027). You self-assess and pay the 22% then. Because nothing is withheld during the year, set the cash aside when you sell — a large December sale can create a sizeable May tax bill you must fund yourself.
If you are a US citizen or green-card holder resident in Korea, the same sale is also reportable to the IRS. The two systems are reconciled through foreign tax credits: generally you can credit the Korean capital-gains tax against your US tax on that gain (or vice versa, depending on sourcing and the treaty), so you are not taxed twice on the full amount. The mechanics are intricate — sourcing of capital gains, the US-Korea treaty, and timing differences all matter — so coordinate both returns rather than treating them in isolation.
This page covers capital gains on selling shares. Dividends from US stocks are a different category: US tax is typically withheld at source (often 15% under the treaty), and the dividend is then included in your Korean taxable income, with a credit for the US tax withheld. Keep dividends and capital gains mentally separate — they have different rates, withholding, and reporting.
The core computation — won cost basis, won proceeds, the 2.5M annual deduction, and the flat 22% rate — matches Korea's overseas capital-gains method and is reliable. It does not automatically pull historical FX rates (you enter them), net every loss, or compute the US-side credit. Treat the result as an accurate Korean-tax estimate for the inputs given, and confirm the exact figures and FX sources with the National Tax Service or a tax adviser at filing time.
For Korean tax residents, gains on US stocks are overseas capital gains taxed at a flat 22% (20% national plus a 2% local surtax) on the net gain above a 2.5 million KRW annual basic deduction. Your US broker does not withhold Korean tax, so you self-report and pay it in your May return.
In won. Korea converts your purchase cost at the exchange rate on the buy date and your proceeds at the rate on the sell date, then taxes the won difference. Because the won/dollar rate moves, your Korean taxable gain can be larger or smaller than the dollar gain your brokerage shows.
Every resident gets a 2.5 million KRW basic deduction against total overseas capital gains each year, not per trade. You pool all foreign gains for the year, subtract one 2.5M deduction, and apply 22% to the remainder.
Yes, within the same tax year. Overseas capital losses offset overseas capital gains realized in that year, so you are taxed only on the net. Korea generally does not allow a net overseas capital loss to be carried forward, so realizing offsetting losses in the same year is the way to reduce the tax.
Overseas capital gains are reported in your annual return filed in May of the year after the sale, and you self-assess and pay the 22% then. Since nothing is withheld during the year, set the cash aside when you sell, especially for large year-end sales.
Generally no. US citizens and green-card holders resident in Korea report the same sale to the IRS, and the two systems are reconciled with foreign tax credits so the gain is not taxed twice on its full amount. The sourcing rules and the US-Korea treaty are intricate, so coordinate both returns.
No. Dividends are a separate category from capital gains. US tax is usually withheld on dividends at source (often 15% under the treaty), and the dividend is then included in your Korean income with a credit for the US tax withheld. This page covers capital gains on selling shares, not dividends.