Compound Interest Calculator
Estimate how an invested capital grows with regular contributions, factoring in the effect of compound interest over time.
Parameters
Calculation convention: the rate entered is an effective annual rate, converted to an equivalent monthly rate ((1 + r)^(1/12) − 1) — never a simple division by 12. Contributions are simulated at the end of each month.
Estimated results
These results are based solely on the assumptions you entered — never a guarantee or a personalized investment recommendation.
Estimated final capital
€107,693.87
Total contributions
€58,000.00
Estimated gains generated
€49,693.87
Share of gains in the final capital
46.1%
Capital growth over time
Understanding compound interest
The effect of compound interest
Each year, the gains produced by your savings themselves generate further gains the following year. This "snowball" effect is small at first, then accelerates markedly over time.
The importance of time
The longer the time horizon, the larger the share of gains in the final capital compared to the amounts actually paid in. Starting early often matters more than the initial amount invested.
The effect of regular contributions
Regular monthly contributions, even modest ones, add to the interest already generated and amplify the effect of compound interest over time.
Keep in mind
- This simulation is educational: it is not a forecast.
- The annual return entered is an assumption, not a guaranteed figure.
- Real returns vary over time and can be negative in some years.
- Fees, taxes and inflation can meaningfully change the result obtained.
- Past performance is never indicative of future performance.
No data from this simulation is stored: all calculations stay in your browser.