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Foreign Stock Capital Gains Tax Calculator

For Korean residents. Applies separate buy/sell exchange rates, KRW 2.5M annual deduction, and 22% (income 20% + local 2%) tax rate.

Purchase

Sale

Options

Result

Enter purchase and sale information then click Calculate.

What this tool does

The Foreign Stock Capital Gains Tax Calculator computes the tax for a Korean resident selling overseas shares (US, Japan, China, etc.). It converts the gain to KRW using the official exchange rate at both the purchase and sale dates, then applies the 2.5 million KRW annual deduction and the 22% rate (20% income tax + 2% local tax). If you already used part of the deduction on another holding this year, enter it in the 'deduction already used' field to apply only the remainder. Results are a preliminary simulation for the May Hometax filing; inputs are processed in your browser and never sent to a server.

Who uses this

  • Estimate tax before the May final filing after selling US stocks (S&P 500 ETFs or single names)
  • In a high-volatility year, simulate how the gap between the buy-date and sell-date exchange rates affects tax
  • Year-end loss-offset strategy: sell losing positions before winners to lower the taxable base
  • Plan sales within the 2.5M KRW deduction: back-calculate the gain that keeps tax at zero
  • Gauge the taxable gain on holdings before transferring proceeds to an ISA or pension account

How to use (4 steps)

  1. 1Enter the buy price (in foreign currency) and the exchange rate at purchase. Find the official rate at the Bank of Korea ECOS (ecos.bok.or.kr) or the 'applied rate' on your brokerage statement.
  2. 2Enter the sell price (in foreign currency) and the exchange rate at sale. If you bought the same stock multiple times, use the weighted-average unit cost.
  3. 3Enter transaction costs (fees + taxes, in KRW). For US stocks this includes brokerage commissions plus the SEC sell fee. Costs are subtracted from the gain.
  4. 4If you already used part of the annual deduction on other foreign-stock gains this year, enter it under 'deduction already used' (0 if none). Click Calculate to see the taxable base, tax, and after-tax profit step by step.

Formula (Income Tax Act §94·§104)

① KRW buy = buy price (foreign) × buy-date rate ② KRW sell = sell price (foreign) × sell-date rate ③ Capital gain = ② − ① − transaction cost (KRW) ④ Remaining deduction = 2,500,000 KRW − deduction already used this year ⑤ Taxable base = max(0, ③ − ④) ⑥ Capital gains tax = ⑤ × 22% (20% income tax + 2% local tax) ⑦ After-tax profit = ③ − ⑥ - The 22% rate is a flat rate regardless of income size - The 2.5M KRW deduction resets once per year - Exchange rate: official rate at the buy date and sell date — so FX moves also affect the gain

Worked examples

Example 1: 5M KRW gain on US stock — full deduction available

Capital gain 5,000,000 − deduction 2,500,000 = taxable base 2,500,000 KRW Tax = 2,500,000 × 22% = 550,000 KRW After-tax profit = 5,000,000 − 550,000 = 4,450,000 KRW → Effective rate on the gain is 11%. The 2.5M deduction softens the burden.

Example 2: FX effect — dollar gain but the KRW gain vanishes

Buy: $100 × 1,350 KRW = 135,000 KRW Sell: $110 × 1,230 KRW = 135,300 KRW A +10% gain in dollars, but only 300 KRW (+0.2%) in won → With a 300 KRW gain, it falls within the 2.5M deduction — zero tax A classic case where the FX drop offset the price rise.

Example 3: Loss offset — sell the losing name first this year

Stock A gain 6M KRW, Stock B loss 2M KRW (sold the same year) Net gain = 6M − 2M = 4M KRW Taxable base = 4M − 2.5M deduction = 1.5M KRW Tax = 1.5M × 22% = 330,000 KRW vs filing only the 6M gain without offset: (6M − 2.5M) × 22% = 770,000 KRW → ~440,000 KRW saved.

Frequently asked questions

When do I file foreign-stock capital gains tax?

You file the final return at Hometax (hometax.go.kr) from May 1 to May 31 each year, covering sales from January 1 to December 31 of the prior year. Failing to file triggers a non-filing penalty (20%) plus a late-payment penalty.

How do I make the most of the 2.5M KRW deduction?

If your total annual foreign-stock gain (after loss offset) is 2.5M KRW or less, the tax is zero. Many investors time their realizations to stay at or under 2.5M ('tax harvesting'). The deduction is calculated separately from domestic stock and real-estate gains.

Which exchange rate should I use?

Use the Bank of Korea base rate (the standard reference rate). Apply the rate for the actual transaction date — the acquisition date for the buy and the transfer date for the sell. You can back-calculate from the 'KRW-converted amount' on your brokerage statement or look it up directly at ECOS (ecos.bok.or.kr).

Can I offset domestic-stock losses against foreign-stock gains?

Under current law, domestic listed-stock gains/losses and foreign-stock gains/losses cannot be offset against each other. Foreign stocks can offset each other within the same year. Even after the 2025 repeal of the financial-investment income tax, foreign stocks keep the separate 22% regime.

Are foreign ETFs and single stocks taxed at the same rate?

If you buy an ETF listed on a foreign exchange through a Korean broker, it is taxed like a single stock at 22% on the gain. However, a foreign-index ETF listed on a Korean exchange (e.g. TIGER US S&P500) has its gains taxed as dividend income (15.4%) and is outside this tool's scope.

What counts as transaction costs?

For US stocks, the main items are brokerage commissions (buy + sell) and the SEC sell fee (sale amount × about 0.00278%). Korea's securities transaction tax does not apply to foreign stocks. Transaction costs are subtracted from the gain, which lowers the tax.

Cautions

  • •This calculator simulates a single trade. If you bought the same stock multiple times, compute and enter the weighted-average cost yourself.
  • •Compute your full annual taxable base by summing all foreign-stock trades and file accordingly; this tool handles only one trade.
  • •A foreign-index ETF listed on a Korean exchange is subject to dividend income tax (15.4%), not capital gains tax, so it differs from this tool.
  • •Exchange rates, tax rates, and deduction limits change when laws are amended. Confirm the exact filing via Hometax or a tax accountant.
  • •Results are for reference only and have no legal force. For large amounts or complex trades, consult a licensed tax accountant.

Last reviewed: 2026-06-17

Foreign Stock Capital Gains Tax | Workmate