Compound interest
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Compound Interest Calculator
Calculate future value with compound interest, initial capital and recurring monthly or yearly contributions.
About this compound interest calculator
This free compound interest calculator helps you estimate how money can grow over time when interest is reinvested and regular contributions are added.
How it works
Enter your initial capital, contribution amount, years, interest rate and compounding frequency. Contributions can be monthly or yearly and can be added at the beginning or end of each period.
Frequently asked questions
- What is compound interest? ▾
- Compound interest is interest calculated on both the initial principal and the interest that has already accumulated. This means your money grows faster over time because you earn interest on your interest, not just on your original investment.
- How does compounding frequency affect growth? ▾
- The more often interest compounds, the faster your money grows. Monthly compounding produces more growth than yearly compounding for the same annual interest rate, because interest is added to the principal more frequently.
- What is the difference between adding contributions at the beginning vs at the end? ▾
- Adding contributions at the beginning of each period means each contribution earns interest for one full period longer than if added at the end. Over many years this difference can add up to a significant amount.
- What interest rate should I use? ▾
- Use the annual interest rate (APY or annual return) for your investment. For savings accounts this is shown as APY. For investment portfolios, historical average annual returns for global stock indices have been around 7–10% before inflation.
- Is this compound interest calculator free? ▾
- Yes, completely free. No sign-up, no download and no ads. All calculations run in your browser and no data is sent anywhere.