Compound Interest Calculator
Discover the "Eighth Wonder of the World". See how your money grows exponentially.
Wealth Accumulator
Projected Future Balance
Breakdown
What is Compound Interest?
Compound interest is the concept of earning interest on your interest. It is the result of reinvesting earnings, rather than paying them out, so that interest in the next period is then earned on the principal sum plus previously accumulated interest. This creates a snowball effect that causes wealth to generate at an accelerated pace over time.
The Compound Interest Formula
While this calculator handles the complex math for you (including monthly contributions), the core formula for a lump sum investment is:
- A: The future value of the investment/loan, including interest.
- P: The principal investment amount.
- r: The annual interest rate (decimal).
- n: The number of times that interest is compounded per unit t (frequency).
- t: The time the money is invested for, in years.
Why Frequency Matters
The more frequently interest is compounded, the more money you earn. For example, 10% interest compounded Daily yields more than 10% compounded Annually because the interest is added to your balance 365 times a year instead of just once.
Simple Interest
Interest is calculated only on the principal portion. Your money grows linearly.
Compound Interest
Interest is calculated on the principal AND accumulated interest. Your money grows exponentially.
Real-World Example
Imagine investing $5,000 initially, with a $200 monthly contribution at 8% interest for 20 years.
- Total you put in: $53,000 (Principal + Contributions).
- Total Interest Earned: Over $65,000.
- End Value: Over $118,000.
Notice that the interest earned is actually higher than the total amount of money you deposited. That is the power of long-term compounding.
Disclaimer & Legal Notice
Estimations Only: The results provided by this Compound Interest Calculator are for illustrative purposes only. The calculations assume a fixed rate of return and that interest is compounded exactly as scheduled without withdrawals or tax implications.
Market Volatility: Actual investments fluctuate in value. Past performance of an asset class (like stocks or bonds) is not a guarantee of future returns.
Not Financial Advice: This tool does not constitute financial, legal, or tax advice. We recommend consulting with a qualified financial advisor before making investment decisions.
Privacy: We respect your data privacy. All inputs are processed locally within your browser. No financial information is stored on our servers.