Calculation Methodology
We transparently disclose how this service calculates returns. Following E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness) principles, we specify every calculation method.
Return Calculation
Cumulative Return
Total principal is the sum of all purchase amounts. The valuation is units held × current (or reference-date) price.
Annualized Return (CAGR)
Used for lump-sum investing. It represents the annual return on a compounding basis.
XIRR (Internal Rate of Return)
XIRR is used when cash flows occur at multiple points, as with recurring (periodic) investing. It reflects the date and amount of each investment and the final value. It may not converge in extreme scenarios, in which case it is shown as "cannot be calculated."
Maximum Drawdown (MDD)
It represents the largest decline from a peak during the investment period, based on the underlying asset price. For lump-sum investing, the units held stay constant, so the asset-price MDD and the account-value MDD are identical. For recurring (periodic) investing, units held increase with each purchase, so the account-value MDD can differ from the asset-price MDD. This service applies daily prices to the cumulative units held at each actual purchase point to compute the MDD on an account-value basis. Because it uses daily price data, it avoids missing troughs that monthly sampling would cause.
Note: Calculating based on month-end closing prices can miss the actual intra-period trough and understate the MDD. This service calculates MDD based on daily closing prices to resolve this issue.
Pre-Tax Treatment Policy
The results of this service are calculated on a pre-tax basis. Actual proceeds may vary depending on taxes and other factors.
Why taxes are not included in the results:
- •Tax rates vary by an individual's income level, country of residence, and account type (general, ISA, pension)
- •Overseas ETFs and domestic ETFs have different tax rate systems
- •Tax categories are complex, including dividend income tax, capital gains tax, and financial investment income tax
- •Tax laws change frequently
Difference from actual investment results: When capital gains tax (22% in Korea, with a 2.5 million KRW deduction), dividend income tax (15.4%), and the like are applied, the actual after-tax return can be lower than the figures shown in this service.
Exchange Rate Treatment
When investing in overseas assets (denominated in USD) with Korean won (KRW), exchange rate changes affect returns.
KRW-Converted Return
Won is converted to dollars at the exchange rate at the time of purchase, and converted back to won at the exchange rate at the time of sale. This calculates the real return that includes exchange rate changes.
USD-Basis Return
Excluding exchange rate changes, the return is calculated from the asset's own price movement alone. The difference between the two returns is the FX effect.
Data Sources
Price Data
Uses adjusted close prices from major financial data providers. Adjusted for dividends and stock splits.
Exchange Rate Data
Based on the Bank of Korea reference rate or major FX data providers.
Inflation Data
Korean Consumer Price Index (CPI): Statistics Korea. U.S. CPI: BLS (U.S. Bureau of Labor Statistics).
Data Limitations
- ⚠The available data period varies by asset. Some assets only have data for the last few years
- ⚠For non-trading days (weekends, holidays), the previous trading day's price is applied
- ⚠Data for delisted assets is not included (beware of survivorship bias)
- ⚠The raw price data is not disclosed externally as a matter of policy
Raw Data Non-Disclosure Policy
This service does not directly download or externally expose the raw price data (such as CSVs). All calculations are performed server-side, and only the result values (return, MDD, XIRR, etc.) are provided to users. This is for the purpose of complying with the data providers' terms of use and managing data quality.
📋 Results are based on historical data; past returns do not guarantee future returns.
📋 This service is provided for educational purposes to help you understand investing, not as investment advice.