Shared rules
Rules shared by every calculator
Currency and amounts
Currency is selected independently from the display language. KRW accepts amounts from ₩100,000 to below ₩1 trillion, while USD accepts $100 to below $1 billion. No exchange-rate conversion is performed when switching currency, and amounts are displayed as whole currency units.
Rates and periods
Returns, interest rates, dividend yields, dividend growth rates, and inflation rates must be between 0% and 100%. Investment periods are 1–50 years and loan terms are 1–600 months.
Monthly calculations
For monthly calculations, the entered annual rate is divided by 12. A month's return is applied before the contribution or withdrawal is made at month-end.
Display and rounding
Calculations retain fractional amounts internally and display whole dollars. Required monthly contributions are rounded up so the target is not missed, while sustainable monthly withdrawals are rounded down to avoid withdrawing more than the modeled balance supports.
Common exclusions
Every result is a simplified estimate that assumes the inputs remain constant. Unless stated otherwise, taxes, fees, exchange rates, inflation, market volatility, and product-specific terms are excluded.
By calculator
Formulas and assumptions
Deposit Interest Calculator
Calculates simple or monthly compound interest and maturity value for one lump-sum deposit held to maturity.
Assumptions
- Monthly compounding applies annual rate ÷ 12 to the full deposit each month
- Tax applies only to interest
- Interest is assumed to be paid at maturity
- Early withdrawal, bonus-rate eligibility, and product-specific day counts are excluded
Recurring Savings Calculator
Calculates simple or monthly compound interest and maturity value for equal monthly savings deposits.
Assumptions
- Monthly compounding applies annual rate ÷ 12 to each deposit for its remaining months
- The first deposit earns interest for the full term and the last for one month
- Tax applies only to interest
- Early withdrawal, government contributions, and bonus-rate eligibility are excluded
Loan Interest Calculator
Calculates monthly principal and interest for a fixed-rate loan using level payment, equal principal, or bullet repayment.
Assumptions
- Monthly rate equals annual interest rate ÷ 12
- Only interest is paid during an interest-only period
- Monthly amounts are rounded to fractional currency units and the final principal payment clears the balance
- Daily accrual, variable rates, prepayment penalties, guarantees, and lender-specific fees are excluded
Compound Interest Calculator
The initial investment grows at a constant annual return, with each year's gain reinvested.
Assumptions
- Annual compounding
- No additional contributions
- Cumulative return equals total growth divided by the initial investment
Recurring Investment Calculator
The initial amount is invested from the start, and an equal contribution is added at each month-end.
Assumptions
- Monthly compounding
- Equal contributions at month-end
- Total principal includes the initial amount and every monthly contribution
Dividend Calculator
A simple pre-tax dividend estimate based on the investment and expected annual yield.
Assumptions
- Monthly average equals annual dividend ÷ 12
- Quarterly average equals annual dividend ÷ 4
- Actual payment dates, taxes, and exchange rates are excluded
Monthly Dividend Goal Calculator
Works backward to the required assets and projects a path using current assets and monthly investments.
Assumptions
- Plan assets receive monthly compound total returns before each month-end investment
- Target-period mode divides the future-value shortfall by the month-end annuity factor and rounds up
- Projected monthly dividend equals projected assets × constant yield ÷ 12
- Total return includes reinvested dividends and price changes; taxes and fees are excluded
Dividend Reinvestment Calculator
Every pre-tax dividend is fully reinvested at year-end, and the modeled dividend yield grows each year.
Assumptions
- Full year-end reinvestment
- That year's yield equals initial yield × (1 + dividend growth) ^ elapsed years
- A simplified model that excludes share prices, payment timing, and taxes
Target Asset Calculator
Combines monthly growth of current assets with month-end contributions to solve for the amount needed to reach a goal.
Assumptions
- Required contribution is rounded up to avoid missing the target
- Required contribution is zero if current assets can reach the target on their own
- A planned contribution can also be tested against a maximum 50-year horizon
Inflation-Adjusted Value Calculator
Discounts a future nominal amount by a constant inflation rate to estimate its value in today's money.
Assumptions
- Constant annual inflation
- The future nominal amount itself does not change
- Differences between individual products or spending categories are excluded
Asset Allocation Calculator
Applies target weights to the portfolio total and compares each target amount with current holdings.
Assumptions
- Stock, bond, and cash targets must total exactly 100%
- Adjustment equals target amount - current holding
- Market movement, taxes, and trading fees are excluded
Retirement Withdrawal Calculator
Models assets growing each month before a fixed withdrawal is taken at month-end.
Assumptions
- Depletion periods are checked up to 50 years
- Withdrawal amounts for a fixed period are rounded down to a whole dollar
- Inflation, taxes, fees, and changing returns are excluded
Korean Salary Net Pay Calculator
Estimates monthly take-home pay by applying verified 2026 employee insurance and earned-income withholding rules to taxable Korean salary.
Assumptions
- Annual salary is divided evenly across 12 months
- The payroll policy year follows the verified rules for the selected reference month
- National pension uses reference-month caps and truncates the income base below ₩1,000
- Withholding reflects eligible dependents, children aged 8–20, and the 80/100/120% election
- Income comparison uses the latest loaded NTS statistics as a separate year and is shown as an approximate range, not an exact salary cutoff
- Age comparison reports the difference from the officially published age-group mean; birth-year percentiles are not inferred
- KRW only; bonuses, severance, year-end settlement, and employer reporting differences are excluded
Overall earned-income source: NTS earned-income percentile dataset. The source does not provide salary cutoffs; it contains band aggregates, so the result is shown as an approximate range.
Age-group mean source: Statistics Korea 2024 wage-job income report. Age-group means are not percentiles, and birth-year rankings are not shown because an official source is not available.