주식 복리 계산기
장기 투자의 힘, 복리 효과를 직접 확인해보세요.
Input Information
Result
계산 결과가 여기에 표시됩니다.
"The eighth wonder of the world." — how Albert Einstein reportedly described compound interest.
The Stock Compound Interest calculator is a financial tool that visualizes this powerful principle. See directly how your initial investment and steady monthly contributions combine with an average annual return to produce surprising results.
It is especially useful for long-term planning — building retirement funds or preparing for a child's education. Simulate the future of a long-term, systematic investment in index-tracking ETFs such as the S&P 500 or KOSPI 200.
The calculator is a prediction based on historical data or your expected return and does not guarantee future results. Yet understanding compounding alone makes it a great compass for your financial journey.
Term Glossary
- Compound Interest
- Reinvesting earned returns into principal so assets grow exponentially over time.
- Dollar-Cost Averaging
- Investing a fixed amount at regular intervals to lower the average purchase price and reduce market-timing risk.
- Real Return
- The nominal return minus inflation — the actual increase in purchasing power.
How the Compound Calculation Works
The calculator assumes returns are reinvested at each year-end and the annual contribution is added at the start of the year.
- Year 1 value:
(Initial Investment + (Monthly Contribution × 12)) × (1 + Annual Return)In the first year, initial capital and one year of contributions are combined, then returns are applied at year-end.
- Year 2 and beyond:
(Previous Year Value + (Monthly Contribution × 12)) × (1 + Annual Return)From year two, another year of contributions is added to the accumulated balance and returns compound on the total.
Key variables:
- Initial investment: The seed money. A larger amount lets you enjoy compounding sooner.
- Monthly contribution: The power of systematic investing — consistency beats brilliance.
- Annual return: The engine of growth. The S&P 500's historical average is ~10–12% but is not guaranteed.
- Investment period: The single most important factor for maximizing compounding.
Example (1,000,000 initial, 100,000/mo, 8% annual, year 1)
Year 1 = (1,000,000 + 1,200,000) × 1.08
= 2,200,000 × 1.08 = 2,376,000
From year 2, another year of contributions is added to the prior balance, then 8% compounds on the total.
1. Set a Realistic Return Assumption
High returns are tempting, but unrealistic expectations lead to bad decisions. Use ~10% (S&P 500) as a baseline and compare conservative (5–7%) and optimistic (12–15%) scenarios.
2. Gauge Speed with the Rule of 72
Estimate doubling time without complex math: 72 ÷ annual return (%). At 8%, your money doubles roughly every 9 years.
3. The Magic of Dollar-Cost Averaging
Investing a fixed amount monthly reduces market-timing risk. You buy more shares when prices are low and fewer when high, lowering the average cost — a proven strategy.
4. Don't Forget Taxes and Fees
Results are pre-tax. Securities transaction tax, dividend tax (15.4%), and overseas capital gains tax (22%) all reduce real returns. Use tax-advantaged accounts like pensions or ISA.
5. Real Return After Inflation
Currency loses value over time. If you earn 10% but inflation is 3%, your real gain is ~7%. Plan on real, not nominal, returns.