Compound Interest Calculator
See how your money grows over time with the power of compound interest. Enter your principal, rate, and time to calculate total returns.
How to Use
- Enter your initial investment amount.
- Set the annual interest rate you expect.
- Choose how long you plan to invest.
- Select how often interest compounds (monthly is most common).
- Optionally add a monthly contribution amount.
- Click “Calculate” to see your projected growth.
Frequently Asked Questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. This “interest on interest” effect causes wealth to grow exponentially over time.
How does compounding frequency affect returns?
More frequent compounding (e.g., daily vs. annually) results in slightly higher returns because interest is calculated and added to the principal more often.
What is the Rule of 72?
The Rule of 72 is a quick way to estimate how long it takes for an investment to double. Divide 72 by the annual interest rate — for example, at 8% interest, your money doubles in approximately 9 years.
Is this calculator accurate for real investments?
This calculator provides estimates based on a fixed rate of return. Real investments may have variable returns, fees, and taxes that affect actual outcomes.