What is Compound Interest?
Compound interest is the process of earning interest not only on your initial investment, but also on the interest that accumulates over time. In simple terms, your money grows faster because you earn interest on interest.
This is one of the most powerful ideas in finance and long-term investing. The longer your money stays invested, the more powerful compounding becomes.
Compound Interest Formula
The formula used in this calculator is:
Final Value = Initial Investment × (1 + r)t
r = annual interest rate in decimal form
t = number of years
Why Compound Interest Matters
Compound interest is the key difference between slow growth and exponential growth. Starting early gives compounding more time to work.
- Grow wealth faster over time
- Benefit from long-term investing
- Turn small investments into larger returns
- Outperform simple interest strategies
Simple vs Compound Interest
Unlike simple interest, which only applies to the original investment, compound interest continuously builds on previous gains.
- Simple Interest: earns interest only on the initial amount
- Compound Interest: earns interest on both the initial amount and accumulated interest
How to Use This Calculator
- Enter your initial investment
- Enter the annual interest rate
- Enter the number of years
- Click calculate to see your future value
Frequently Asked Questions
Compound interest can be calculated at different intervals such as daily, monthly, or yearly. This calculator uses annual compounding for simplicity.
The longer your investment stays invested, the more powerful compounding becomes, leading to much stronger growth over time.
Yes. Even small increases in the annual interest rate can significantly boost your final value over long periods.
Yes. Reinvesting earnings is essential if you want to benefit fully from compound interest.
Yes. Even small amounts can grow substantially if they are invested for a long enough time with compounding.
A good interest rate depends on the investment type, but historically, stock markets average around 7–10% annually.