Shared rules
Rules shared by every calculator
Currency and amounts
Currency is selected independently from the display language. General amount inputs accept ₩100,000 to below ₩1 trillion or $100 to below $1 billion. Stock average cost prices and quantities have separate bounds and accept whole numbers only. CAGR accepts whole-number starting values from 1 and ending values from zero. No exchange-rate conversion is performed when switching currency.
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; general calculators display whole currency units. Stock average cost displays prices up to eight decimals and totals as whole KRW or two-decimal USD. CAGR displays amounts as up to two-decimal KRW or two-decimal USD. 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
01
Overseas Stock Capital Gains Tax Calculator
Combine realized gains on overseas-listed stocks and on-exchange ETF sales taxed as stock capital gains at the general 20% Korean national rate.
FormulaQ=max(0,P−D); T=floor(Q×incomeRate)+floor(Q×localRate); H=max(0,D−P); afterTax=P−T; P2=P+additionalProfit
Assumptions
- Only reviewed 2026 rules are selectable; default to the current Korean year if supported, otherwise the latest reviewed year
- Whole KRW only. Each amount and combined profit are bounded by absolute KRW 999999999999. No currency conversion or live FX
- Combine one person’s same-year eligible accounts and apply the verified remaining shared deduction once. Domestic stock offsets and other tax rates require separate calculations
- Calculate each tax with exact decimal arithmetic, truncate below one KRW, then sum. Official filing/payment truncation and actual tax may differ
- Gain headroom includes loss offsets. It is neither sale proceeds nor remaining basic deduction. Net losses do not imply refunds
- Exclude dividends, unrealized gains, other-year losses, Korea-listed overseas ETFs, gifted-stock basis relief, foreign tax credits, RIA, ETF liquidation and off-exchange transfers
- General resident rules require continuous Korean domicile or residence for at least five years through the sale date. File in May next year; zero tax does not establish no filing obligation
02
Korean Severance Pay Calculator
Estimates pre-tax Korean severance using the general formula; eligibility is not adjudicated.
FormulaSeverance = applied daily wage × 30 × employment days ÷ 365
Assumptions
- Includes the hire and last employment dates; retirement is the following day. The one-year condition compares retirement with the first hire anniversary; a February 29 hire must include the last day of the following February
- Uses the three calendar months preceding retirement, capped at the hire date for short employment. Month subtraction clamps to month-end
- Assumes the entered monthly gross wage stays constant throughout the final three months. Prorates by calendar days and rounds each period to whole KRW with HALF_UP; actual pay changes are not included
- Adds 3/12 of eligible annual bonuses and leave payments. Do not also include them in period wages
- The public calculator estimates using average wage only. A higher statutory ordinary wage could increase the legal amount; this comparison is not included
- Division uses 24 significant digits with HALF_UP; displayed amounts round to whole KRW with HALF_UP and are never reused in calculations
- Payment deadlines are not calculated. The FAQ explains the general payment rule
- KRW only, without FX conversion. Excludes after-tax proceeds, DC balances, leave exceptions, varying hours and prior settlements. Official sources checked 2026-10-07
03
Exchange Rate Calculator
Converts USD/KRW and estimates costs from an entered spread/discount and currency gains.
FormulaUSD→KRW = amount × rate; KRW→USD = amount ÷ rate; gain = sale proceeds − purchase outlay
Assumptions
- Rates mean KRW per 1 USD, independently of language and global display currency
- Uses the latest stored close or a manual rate. Dates after today in Seoul are excluded. Latest rows with missing/invalid closes or more than seven weekdays of age are not automatically used; weekday holidays count
- Remaining one-way spread = base spread × (1 − discount / 100). Cost estimates assume the same percentage on both legs; stored quotes are not bank reference rates
- Uses the actual purchase rate and separate buy/sell charges. Do not count spreads already included in customer rates twice
- Products and sums retain exact decimal values; division uses 24 significant digits with HALF_UP. Final display rounds HALF_UP to whole KRW, two-decimal USD and up to eight-decimal rates
- Share links preserve the numeric rate as a manual input. Taxes, interest and future market changes are not automatically included; results are not advice or a guarantee of returns
04
Deposit Interest Calculator
Calculates simple or monthly compound interest and maturity value for one lump-sum deposit held to maturity.
FormulaSimple interest = deposit amount × annual rate × months ÷ 12
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
05
Recurring Savings Calculator
Calculates simple or monthly compound interest and maturity value for equal monthly savings deposits.
FormulaSimple interest = monthly deposit × annual rate ÷ 12 × months × (months + 1) ÷ 2
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
06
Loan Interest Calculator
Calculates monthly principal and interest for a fixed-rate loan using level payment, equal principal, or bullet repayment.
FormulaLevel payment = principal × monthly rate × (1 + monthly rate)^months ÷ ((1 + monthly rate)^months - 1)
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
07
Loss Recovery Calculator
Calculates the gain on remaining capital needed to restore the original value.
FormulaRequired gain = loss percentage ÷ (100 − loss percentage) × 100
Assumptions
- Enter a positive loss magnitude from 0 to 100%, with up to two decimals
- Zero loss needs zero gain; a 100% loss leaves no capital and cannot be recovered through a return alone
- Original value is normalized to 100; remaining value is 100 minus loss percentage. Independent of amounts and currency
- Exact decimal subtraction; required gain rounds to six decimals and recovery multiple to twelve decimals with HALF_UP. Display rounds to two decimals with HALF_UP
- No automatic cash flows, taxes, fees, dividends, FX or inflation. Does not forecast recovery time or future returns
08
CAGR Calculator
Calculates the equivalent constant annual compound growth and total change between starting and ending values.
FormulaCAGR = [(ending value ÷ starting value) ^ (1 ÷ years) − 1] × 100
Assumptions
- Elapsed years = (years × 12 + months) ÷ 12. Supports 1 month to 50 years; differs from the actual days ÷ 365.2425 convention used in date-based backtests
- Starting amount is at least 1; ending amount is at least 0. Both accept whole numbers only, with maxima of 999999999999 KRW or 999999999 USD
- Value differences use exact decimal arithmetic; division uses 24 significant digits with HALF_UP. Exponentiation uses floating point, then percentage results round to six decimals with HALF_UP
- Display uses two-decimal percentages, up to two-decimal KRW and two-decimal USD with HALF_UP. Very large percentages use scientific notation. Display rounding is not reused in calculations
- Zero ending value gives −100% CAGR and total change; unchanged value gives 0%. Negative values are unsupported
- Assumes no intervening deposits or withdrawals. CAGR does not mean the same growth occurred every year; cash flows require a separate measure such as XIRR
- Sub-year results are annualized, not forecasts. Taxes, fees, dividends, inflation and currency conversion are not automatically included
09
Compound Interest Calculator
The initial investment grows at a constant annual return, with each year's gain reinvested.
FormulaFinal assets = initial investment × (1 + annual return) ^ years
Assumptions
- Annual compounding
- No additional contributions
- Cumulative return equals total growth divided by the initial investment
10
Recurring Investment Calculator
The initial amount is invested from the start, and an equal contribution is added at each month-end.
FormulaMonth-end assets = opening assets × (1 + annual return ÷ 12) + monthly contribution
Assumptions
- Monthly compounding
- Equal contributions at month-end
- Total principal includes the initial amount and every monthly contribution
11
MDD Calculator
Measures daily drawdowns and independent episodes from the first split-adjusted close within the selected period.
FormulaDD = (P / running peak − 1) × 100; MDD = min(DD)
Assumptions
- Excludes dividends, pre-period peaks, FX and costs. Equal peaks use the latest date; equal troughs use the earliest. Trading durations count observed index differences; calendar durations count date differences. Open episodes use elapsed time to the last observation. Ulcer Index is the root mean square of all daily DD percentages. Decimal arithmetic: 24 significant digits HALF_UP; display: 2 decimals. Observation shares are not future probabilities. Scenario currency is KRW/USD without FX conversion.
12
Investment Backtest
Simulates a single-asset lump-sum or monthly plan across historical daily price movements and compares it with a benchmark.
FormulaDaily value = shares held × split-adjusted close + remaining cash
Assumptions
- Start dates can be selected from January 1, 2006; the actual comparison start is the latest of the requested start, the target asset's first data date, and the benchmark's first data date
- Lump-sum plans use CAGR (annualized return) from the actual purchase date to valuation; monthly plans use XIRR (annualized money-weighted return) across dated cash flows
- MDD is the largest decline relative to the prior highest valuation; lump-sum plans use actual daily portfolio values. Ratios are compared without rounding to select the interval; the result percentage is rounded to six decimal places
- Equal peaks keep the earliest date; equal MDDs keep the earliest trough. The loss amount is the peak-to-trough difference for that MDD interval, not a separately maximized cash loss
- Recovery is the first date after the selected trough reaching or exceeding its peak. Recovery days are calendar days from trough to recovery; unrecovered periods have no recovery date or duration, and no decline uses the first date and zero days
- Target and benchmark MDD use the same rule independently; monthly plans use each asset's own time-weighted performance series, removing its external contributions after its resolved contribution-date close valuation
- Monthly loss is the decline in that series scaled to the first portfolio valuation, including that day's contribution. It is not an actual account loss or the point difference of a base-100 index
- Prices exclude cash-dividend adjustments
- Purchases move to the next trading day and final valuation uses the previous trading day
- Korean assets use whole shares with remaining cash; US assets allow fractional shares
- The same dividend mode applies when both target and benchmark are inside their stored market-data ranges; one side is never silently excluded
- US cash-dividend and reinvestment modes use stored reported cash dividends and do not imply official-source reconciliation; Korean stocks and ETFs support price-only backtests
- Official total-return figures may use NAV or index prices, ex-date reinvestment and fractional units, unlike this market-close, next-trading-day model
- Gross dividend entitlement uses holdings immediately before the ex-date and excludes same-day purchases; reinvestment is modeled at the next stored trading-day close
- Cash dividends stay separate from contributions, while pending reinvestment cash and whole-share remainders remain in portfolio value without becoming external cash flows
- When currencies differ, USD/KRW uses the same-day or prior valid rate within seven weekdays; calculation stops beyond that gap
- Buy/sell commissions and FX costs are currently zero but are designed for a future cost policy
- Only assets in the selection list can be used; results are not investment advice and do not guarantee actual returns
We collect and review price, dividend and exchange-rate data date by date. This takes time, so updates may lag behind the latest available data. Please check the data reference date when using the information.
13
Leveraged ETF Effect Calculator
Compares LONG product leverage using stored prices or manually entered start and end prices.
FormulaRealized leverage = product cumulative return / underlying cumulative return; efficiency = realized / target × 100; relative to target = efficiency − 100%
Assumptions
- Manual mode uses four prices and an integer target from 1x to 10x without stored-price lookup or a start-date chart. Use the same dates and consistent currencies and split-adjustment bases per asset. Prices must be positive, at most 1 trillion, with up to 8 decimal places
- Price returns use ending / starting split-adjusted close minus one. Dividends, personal taxes, trading fees, inflation and FX conversion excluded; fund costs remain reflected in prices
- ETF lookup mode uses the first and last common price dates inside the requested range. Dates before the current target regime are rejected. At least two common dates required
- No multiple or efficiency when absolute underlying return is below 3% or signs differ. Within ±3% of target is similar. Declines use realized loss leverage
- ETF lookup mode: fixed end date; daily common dates up to one year, first weekly common dates up to three years, first monthly common dates thereafter. Unavailable intervals break the chart line
- Intermediate calculations use DECIMAL128; display uses two-decimal HALF_UP. Ratios have no currency conversion
- QQQ is a Nasdaq-100 proxy ETF; SOXX is a reference ETF, not the exact SOXL index. Period ratios are neither daily exposure nor isolated compounding. Historical comparisons are not investment advice or return guarantees
14
Lump Sum vs Monthly Investing
Compares lump-sum and full-period monthly deployment of the same total budget into one asset. Returns are price-only.
FormulaTotal assets = holdings + trade remainders + waiting cash; return = (total assets - initial cash) / initial cash × 100
Assumptions
- Uses split-adjusted closes we collect and store for US and Korean assets, with existing price/calendar checks
- Monthly timing options: first-purchase anniversaries, the 1st, the 15th, the last calendar day or a custom day from 1 to 31 (clamped to month-end). Calendar timing skips dates before the later of requested/data start and counts through requested end. Execution moves to the next stored trading day; installments after valuation stay as cash
- The default start-date monthly plan counts original first-purchase-date monthly anniversaries through the actual valuation date, inclusive. Divide the budget by that count. Both strategies assume the full initial budget is available
- Lump sum buys the full budget on the first available trading day. Monthly investing buys on or after each scheduled date using the selected monthly timing
- Both strategies share the last stored valuation date inside the period. Unexecuted installments stay as waiting cash
- Waiting cash stays in the input currency at 0% interest. Holdings and trade remainders use the asset currency; cross-currency values use existing USD/KRW rates with a seven-weekday lookback limit
- Installments round down to two decimals; the last clears the principal remainder. Intermediate arithmetic uses 24-digit HALF_UP; money rounds to two and percentages to six decimal places
- Korean whole shares and US fractional shares rounded down to eight decimals. Display uses whole KRW or two-decimal USD
- Drawdown uses total assets including waiting cash relative to their previous peak. There are no external monthly contributions
- Dividends, taxes, trading/FX fees, inflation and waiting-cash interest are excluded. Historical results do not guarantee future returns
15
Dividend Calculator
A simple pre-tax dividend estimate based on the investment and expected annual yield.
FormulaAnnual dividend = investment × annual dividend yield
Assumptions
- Monthly average equals annual dividend ÷ 12
- Quarterly average equals annual dividend ÷ 4
- Actual payment dates, taxes, and exchange rates are excluded
16
Monthly Dividend Goal Calculator
Works backward to the required assets and projects a path using current assets and monthly investments.
FormulaRequired investment = target monthly dividend × 12 ÷ annual dividend yield
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
17
Dividend Reinvestment Calculator
Every pre-tax dividend is fully reinvested at year-end, and the modeled dividend yield grows each year.
FormulaAnnual dividend = opening assets × that year's dividend yield
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
18
Target Asset Calculator
Combines monthly growth of current assets with month-end contributions to solve for the amount needed to reach a goal.
FormulaTarget assets = future value of current assets + future value of monthly contributions
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
19
Inflation-Adjusted Value Calculator
Discounts a future nominal amount by a constant inflation rate to estimate its value in today's money.
FormulaPresent value = future amount ÷ (1 + annual inflation rate) ^ years
Assumptions
- Constant annual inflation
- The future nominal amount itself does not change
- Differences between individual products or spending categories are excluded
20
Stock Average Cost Calculator
Combines existing holdings and an additional purchase of one asset to compare average cost, invested capital and unrealized returns.
FormulaNew average cost = (existing average × shares held + purchase price × added shares) ÷ total shares
Assumptions
- Existing and added shares refer to one asset in one currency, with no sales
- Prices and quantities range from 1 to 999999999; optional current price ranges from 0 to 999999999. All inputs must be whole numbers
- Products and sums retain exact decimal values; division uses 24 significant digits with HALF_UP
- Average prices display up to eight decimals and quantities as whole numbers; monetary totals display whole KRW or two-decimal USD; percentages display two decimals with HALF_UP. Display rounding is never reused in calculations
- Unrealized profit or loss = current price × quantity − invested cost; return = profit or loss ÷ invested cost × 100
- Gain to break even = max(invested cost − valuation, 0) ÷ valuation × 100. A zero current price has no finite recovery percentage; holdings at or above breakeven show 0%
- A lower average cost does not necessarily reduce the loss amount. A purchase at the current price leaves the immediate unrealized loss unchanged
- Uses weighted-average arithmetic. Excludes taxes, fees, dividends, stock splits, currency conversion and live prices. Results do not recommend trades or guarantee returns
21
Asset Allocation Calculator
Applies target weights to the portfolio total and compares each target amount with current holdings.
FormulaTarget amount by asset class = total investment × target weight
Assumptions
- Stock, bond, and cash targets must total exactly 100%
- Adjustment equals target amount - current holding
- Market movement, taxes, and trading fees are excluded
22
Retirement Withdrawal Calculator
Models assets growing each month before a fixed withdrawal is taken at month-end.
FormulaMonth-end assets = opening assets × (1 + annual return ÷ 12) - monthly withdrawal
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
23
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.
FormulaMonthly net pay = gross pay - pension - health - long-term care - employment insurance - income tax - local income tax
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.