Choose whether gains show in red, as at Korean brokers, or in green, as overseas. Your choice is saved on this device.
Calculators
US taxes, paychecks, retirement, mortgages and investing. Run the numbers you need right in your browser.
Taxes & paycheck
See your federal tax, take-home pay and the tax on your investment gains, using the 2026 IRS numbers.
Estimate your 2026 federal income tax, marginal and effective rate by filing status.
Turn gross salary into net pay after federal tax, FICA and state tax.
Short-term and long-term capital gains tax plus the 3.8% NIIT on stock sales.
Retirement
Project your 401(k), compare Roth and Traditional accounts, and test the 4% rule against your savings.
Project your 401(k) balance with the 2026 limits, employer match and catch-up.
Compare after-tax value of Roth and Traditional contributions.
Find your retirement number and see if your savings are on track.
Find the nest egg and the age to reach financial independence with the 4% rule.
Home & loans
Monthly mortgage payments with taxes and insurance, how much house you can afford, and loan payoff plans.
Monthly payment with taxes, insurance and PMI, plus an amortization schedule.
How much house you can afford from income, debts and down payment.
Monthly payment, total interest and payoff time with extra payments.
Compare equal-payment, equal-principal and bullet repayment.
Investing & growth
Compounding, DCA, dividends, savings and the cost of leveraged ETFs.
Calculate how much your principal and monthly contributions grow with compounding, and how much you need each month to reach a target amount.
What if you had invested steadily every month in the KOSPI, S&P 500, Samsung Electronics or Bitcoin? Simulated with actual historical data.
Instantly convert period returns into annualized returns (CAGR), and annual returns into period returns.
Calculate future dividends and assets including after-tax dividends, dividend growth and the effect of reinvestment.
Grow a deposit with APY, monthly contributions and compounding.
Simulate for yourself why 2x and 3x leveraged ETFs lose money in a sideways market.
Trading & portfolio
Average price, break-even, position size, rebalancing, ETF overlap and currency conversion.
Calculate your new average price after buying more, and how many shares you need to reach a target average price.
A -50% loss needs a +100% gain. See at a glance the gain required to break even for each loss rate.
Calculate the right number of shares for this trade from your acceptable loss relative to your account and your stop-loss price.
Enter your target weights and it tells you how many shares of each stock to buy or sell.
Ownership and share-price dilution from new shares or convertibles.
Korea-specific tools
These calculators apply Korean tax rules, Korean accounts or Korean market practice, so they are most useful if you invest, work or live in Korea. Amounts are in won by default.
Korea: monthly net pay after the four social insurances and income tax.
Korea: severance pay, retirement income tax and IRP savings.
Korea: estimated National Pension benefit.
Korea: pre- and after-tax interest and maturity value.
Korea: debt service ratio and extra mortgage room with stress DSR.
Korea: legal brokerage fee cap by transaction amount.
Korea: price at which a margin purchase hits forced liquidation.
Korea: equal and proportional IPO allocation and deposit.
Korea: overseas-stock fees and FX discounts across brokers.
Korea: 12 currencies to won with cash and wire spreads.
Korea: split a won return on US stocks into price and currency effects.
Korea: combined exposure across several ETFs.
Korea: build a monthly after-tax dividend calendar.