What is Compound Interest?
Compound interest is the interest on a loan or deposit calculated based on both the initial principal and the accumulated interest from previous periods. In simpler terms, it is "interest on interest," which allows your money to grow exponentially over time.
Albert Einstein famously called compound interest the "eighth wonder of the world" because of its power to generate wealth. The earlier you start saving, the more powerful this effect becomes.
How to Use This Calculator
- Initial Investment: Enter your starting amount (Principal) for your investment.
- Interest Rate: Input the expected annual return rate.
- Years to Grow: How long do you plan to save or invest?
- Monthly Contribution: (Optional) Add a recurring monthly deposit to see how it boosts your total.
- Compound Frequency: Select how often interest is calculated (Monthly is standard for most savings accounts).
The Power of Compounding
To understand the difference between simple and compound interest, consider this example:
- Scenario: Invest $10,000 at 5% for 20 years.
- Simple Interest: You earn $500/year. Total Interest = $10,000. Final Value = $20,000.
- Compound Interest: You earn interest on your interest. Final Value ≈ $26,533. That's an extra $6,533 just from compounding!
Compound Interest Formula
The standard formula for compound interest is:
A = P(1 + r/n)^(nt)
- A = Final amount
- P = Initial principal balance
- r = Interest rate (decimal)
- n = Number of times interest applied per time period
- t = Number of time periods elapsed
Frequently Asked Questions (FAQ)
The more frequently interest compounds, the more money you make. "Daily" compounding yields more than "Yearly" compounding, although for small amounts the difference may be negligible.
No, this calculator shows the nominal future value. To account for purchasing power, you would need to subtract the inflation rate from your expected return rate.
High-Yield Savings Accounts (HYSA) typically offer rates between 3% and 5% depending on the economic environment, while stock market investments historically average around 7-10% annually.