Compound Interest Calculator
See how your investment grows over time with compound interest.
1Investment Details
3Year-by-Year Breakdown
| Year | Invested | Balance | Profit |
|---|---|---|---|
| 1 | 16,000,000 | 16,919,193 | 919,193 |
| 2 | 22,000,000 | 24,338,576 | 2,338,576 |
| 3 | 28,000,000 | 32,294,306 | 4,294,306 |
| 4 | 34,000,000 | 40,825,157 | 6,825,157 |
| 5 | 40,000,000 | 49,972,703 | 9,972,703 |
| 6 | 46,000,000 | 59,781,527 | 13,781,527 |
| 7 | 52,000,000 | 70,299,431 | 18,299,431 |
| 8 | 58,000,000 | 81,577,675 | 23,577,675 |
| 9 | 64,000,000 | 93,671,224 | 29,671,224 |
| 10 | 70,000,000 | 106,639,017 | 36,639,017 |
Guide: The Power of Compound Interest
Compound interest is the most powerful force in investing. Unlike simple interest (which only earns on your original amount), compound interest earns "interest on interest," creating exponential growth over time. The longer you invest, the more dramatic the effect.
Reference rates for planning: Korean bank deposits (적금/예금) typically offer 3~4% annually. The KOSPI (Korean stock market index) has averaged about 7~8% over the long term. Global stock index funds (like S&P 500) have historically returned about 7~10% annually. Higher returns come with higher risk and volatility.
The Rule of 72: This simple formula tells you how long it takes to double your money. Divide 72 by your annual interest rate. At 3% (bank deposit), it takes 24 years to double. At 7% (stock market), about 10.3 years. At 10%, just 7.2 years. This shows why investing in growth assets early is so impactful.
Monthly contributions matter more than you think. Even small regular contributions compound significantly over time. Saving 500,000 won per month at 7% for 20 years gives you about 260 million won — even though you only contributed 120 million won. The other 140 million won is pure compound interest growth.
Start early, stay consistent. A 25-year-old who invests 300,000 won/month until age 65 at 7% will accumulate over 790 million won. A 35-year-old doing the same will only reach about 365 million won. Those extra 10 years more than doubled the final amount — that is the magic of compound interest.