Compound Interest Calculator
Calculate compound interest and estimate investment growth. Compare compounding frequencies, add regular monthly contributions and see your projected final balance.
Enter your investment details
Your investment results
Investment growth chart
Compare your invested amount with the projected balance over time.
Year-by-year growth
| Year | Invested to date | Interest earned | Balance |
|---|---|---|---|
| Calculate your investment to see the yearly breakdown. | |||
How to calculate compound interest
Compound interest is interest calculated on the original principal and on interest accumulated from earlier periods. The investment can grow faster over time when interest is reinvested.
A = P(1 + r/n)nt
Where:
- A = final balance
- P = initial principal
- r = annual interest rate as a decimal
- n = compounding periods per year
- t = investment duration in years
Interest = Final balance − Initial principal
When regular contributions are included, the calculator models monthly deposits and their growth using an equivalent monthly rate derived from the selected compounding frequency.
Frequently asked questions
What is compound interest?
Compound interest is interest earned on both your original investment and previously accumulated interest, assuming the interest remains invested.
Is monthly or daily compounding better?
For the same positive nominal annual rate and principal, more frequent compounding generally produces a higher effective annual rate. The difference depends on the rate and compounding frequency.
How do monthly contributions affect compound interest?
Regular deposits increase the amount invested over time. Deposits made earlier generally have more time to earn returns than deposits made later.
Does this calculator include taxes or fees?
No. Results are before taxes, fees and inflation. Actual returns may also vary if the interest rate changes or the investment carries risk.
Is the projected final balance guaranteed?
No. It is a mathematical estimate based on the inputs supplied, assuming a constant annual rate and the stated contribution schedule. It is not financial advice or a guarantee of future returns.
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