Compound Interest Calculator
See how compound interest grows your money over time. Adjust principal, monthly contributions, rate, and compounding frequency. Shows year-by-year breakdown.
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How to Use This Tool
- Enter your initial principal (starting investment amount).
- Enter the annual interest rate and investment duration in years.
- Choose the compounding frequency (daily, monthly, quarterly, or annually).
- Add regular contributions to see how they accelerate your growth.
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Frequently Asked Questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and accumulated interest from previous periods. It's often called 'interest on interest' and is the most powerful force in growing wealth over time.
How often should interest compound?
More frequent compounding produces higher returns. Daily compounding yields slightly more than monthly, which yields more than quarterly or annually. The difference is small for short periods but significant over decades.
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 your annual interest rate. For example, at 8% interest, your money doubles in approximately 9 years (72÷8=9).
How do regular contributions affect compound interest?
Regular contributions dramatically increase your total growth. Adding even small amounts monthly can multiply your final balance. This is the core principle behind retirement savings plans like 401(k)s.
What is compound interest and why is it important?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. It has a powerful effect on growing wealth over time due to exponential growth.