What This Calculator Does and Doesn't Do
It applies the same principal, period, and assumed return to three paths — direct investing, Pension Savings/IRP, and ISA — and computes what's left after tax in each. Pension Savings/IRP assumes even annual contributions and shows the tax-deduction refund separately (so it doesn't get mixed up with the tax charged on withdrawal). The rules used (rates, thresholds, age bands) are as of 2026 — see Investing in US Stocks via Pension and ISA Accounts for a fuller explanation of the account types themselves.
This is not individual advice. Your actual result depends on your income bracket, existing contributions, other income, and withdrawal timing, and we do not recommend any specific brokerage or product. Confirm actual filing and deductions via Korea's National Tax Service (Hometax) or a tax professional. Results are an approximation for reference and do not substitute for tax consultation. For a detailed direct-investing capital-gains calculation alone, use the overseas stock tax calculator.
Rules like tax rates, deduction limits, and age bands can be revised annually, so we keep them in a single constants file (the rules SSOT) and use those values directly in this calculation. We left out details we weren't confident about — where a rule was ambiguous, we decided it was better to say "confirm with the National Tax Service" than to guess convincingly. Pension Savings/IRP assumes even annual contributions, so if your actual contributions varied year to year, the total tax-deduction figure here may differ from reality.