Compound Interest Calculator
Estimated future value
$0.00
Growth over time
How this calculator works
This calculator assumes monthly compounding and includes both an initial investment and ongoing monthly contributions.
As your balance grows, interest is earned not only on your contributions but also on previous interest. This is what causes growth to accelerate over time.
How this compound interest calculator works
This calculator estimates how your savings or investments grow over time using compound interest. It takes into account your initial investment, ongoing monthly contributions, interest rate, and time horizon.
Interest is compounded monthly, meaning each period’s growth builds on previous gains. Over time, this can lead to exponential growth as your balance increases.
Why compound interest matters
Compound interest allows your money to grow faster than simple interest because you earn returns not only on your original investment, but also on accumulated interest.
The longer your money remains invested, the more powerful compounding becomes. Even small contributions made consistently can grow significantly over time.
Example: Long-term investment growth
If you start with $10,000 and contribute $500 per month at an average annual return of 7%, your investment could grow to a substantial amount over 20 years.
Use the calculator above to adjust the inputs and see how changes in contributions, rate of return, and time affect your results.
Frequently asked questions
What is compound interest?
Compound interest is the process of earning returns on both your initial investment and the interest that accumulates over time. This leads to accelerating growth as your balance increases.
How often is interest compounded?
This calculator assumes monthly compounding. That means interest is applied to your balance once per month.
Are these results guaranteed?
No. This calculator provides estimates based on a fixed rate of return. Actual investment performance can vary depending on market conditions.
Why does growth accelerate over time?
As your balance increases, each period’s interest is calculated on a larger amount. This creates exponential growth, especially over longer time horizons.
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