ISA Calculator

Compare ISA gains, tax treatment, and after-tax outcomes for stock, ETF, bond, RP, and deposit-income scenarios.

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ISA scenario

Choose account and asset branches, then calculate trade or dividend flow in separate tabs.

ISA account type

Asset type

Holding years

years

Common stock or sale inputs

Foreign assets use the exchange-rate field for a simple KRW conversion.

Purchase price

KRW

Sale price

KRW

Quantity

Exchange rate

KRW

Used for foreign stock and foreign ETF branches.

Trade scenario contribution

KRW

20M KRW

Other ISA gains or losses

KRW

ISA outcome comparison

Gains, taxes, and after-tax values are shown side by side for regular accounts and ISA.

Trade gain or loss₩1,500,0001.5M KRW

Net ISA income after offset₩1,500,0001.5M KRW

Modeled exemption₩2,000,0002M KRW

Applied annual contribution limit₩20,000,00020M KRW

Applied total contribution limit₩100,000,000100M KRW

Regular-account tax₩015.4%

ISA tax₩09.9%

After-tax value₩6,500,0006.5M KRW

Tax savings₩0

Notes and assumptions

Domestic listed-stock capital gains are modeled as non-taxable in a regular account; dividends remain taxable.

Financial-income comprehensive taxation eligibility and other account restrictions are not fully modeled.

Reference date: 2026-09-17. ISA exemption, separate-tax, and current contribution-limit assumptions follow the Restriction of Special Taxation Act information available on the reference date. Super ISA limits are modeled from the Financial Services Commission reform proposal.

About ISA Calculator

Compare modeled ISA tax with a regular account for a trade or dividend scenario.

Select an account and asset assumption. Standard ISA uses a 2 million KRW exemption; qualifying low-income/farmer/fisher models use 4 million, with 9.9% on modeled excess income.

Download the scenario to review its assumptions. A computed amount does not establish that an asset is eligible for an ISA or that the whole gain is taxable.

The calculation or rendering runs in this browser tab. Copy, download and share actions make the chosen output available outside this tab.

Worked example

Input / settings: Standard ISA; domestic fund; buy 10,000, sell 13,000, quantity 1,000; other gains 0; 3 years
Action: Calculate the trade scenario
Result: Modeled gain 3,000,000; ISA tax 99,000; proceeds after modeled ISA tax 12,901,000 KRW.

Calculation model

Modeled ISA tax = max(0, max(0, trade gain + other net income) − exemption) × 9.9%.

Dividend mode applies the selected exemption basis to accumulated payouts. For standard term treatment the exemption is not reset each year.

Scope and limits

Super ISA options and annual exemption reset are hypothetical comparisons, not confirmed current-law benefits. Dividend mode uses fixed entered payout assumptions and simplified timing.
Foreign direct-investment selections are comparison scenarios, not ISA eligibility. Domestic-stock exemptions, fund taxable-base price, foreign withholding/credits, fees, full loss-netting rules and early-termination adjustments are not fully modeled.
Standard contribution assumptions are 20 million KRW annually and 100 million total; the tool does not audit other accounts or all carry-forward conditions.

Frequently asked questions

Is the exemption renewed every year under the ordinary ISA rule?: No. The ordinary term basis uses the exemption associated with subscription or extension. Yearly reset is explicitly a comparison assumption.

Sources and review dates

Restriction of Special Taxation Act, Article 91-18 Reviewed 2026-09-17
Ordinary ISA exemptions, term, contribution and tax rules.
Local Tax Act, Article 103-13 Reviewed 2026-09-17
Local income tax on withholding.

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