Compound Interest Calculator
Calculate your future investment value with annual contributions and interest rate. Visualize the power of compound interest with interactive charts.
Last updated:
How to Use
Expand how to useCollapse how to use
- 1
Enter investment parameters
Enter the initial investment, annual contribution, annual interest rate (expected return), and investment period. You can also select the contribution timing (beginning/end of year).
- 2
Review simulation results
The future value, total principal, total interest, and return rate are calculated in real-time. View the power of compound interest visually in the chart.
- 3
Check yearly breakdown
Click 'Show details' to view the detailed breakdown including start balance, contribution, interest earned, and end balance for each year.
Input
Interest calculated before contribution
Result
Enter values to calculate
About Compound Interest Calculator
Compound Interest Calculator is an online tool for calculating the future value of investments and savings. Simply enter the initial investment, periodic contribution, annual interest rate, and investment period to simulate asset growth through compound interest. Visualize your wealth progression with charts and yearly breakdowns to help plan long-term investments.
Key Features
- Compound interest calculation with initial investment and periodic contributions
- Contribution timing selection (beginning/end of year)
- Asset growth chart visualizing principal and interest
- Yearly breakdown showing detailed figures
- Real-time calculation (results update as you type)
Use Cases
- Projecting the future value of a 401(k) or IRA over 20–30 years
- Calculating how much you need to save monthly to reach a retirement goal
- Comparing growth in a high-yield savings account vs an index fund
- Seeing the impact of starting retirement contributions at 25 vs 35
- Planning a college savings fund (529 plan) with regular monthly contributions
- Understanding the long-term effect of different annual return rates (5%, 7%, 10%)
FAQ
What is compound interest?
Compound interest is a calculation method where interest is earned not only on the principal but also on previously accumulated interest. This 'compound effect' can lead to significantly greater growth over long periods compared to simple interest.
What's the difference between beginning and end of year contributions?
Beginning of year contributions are made at the start of each year and earn interest for that entire year. End of year contributions are made at the end of each year and start earning interest the following year. Beginning of year contributions are slightly more advantageous.
Are these calculation results guaranteed?
No, this simulation provides reference values assuming the specified interest rate continues. Actual investments are subject to market fluctuations, and returns are not guaranteed.
Are taxes considered in the calculation?
This simulation does not account for taxes. In practice, investment gains are typically taxed at around 15-20%, but tax-advantaged accounts like 401(k) or IRA can reduce or defer taxes.
Can I enter negative interest rates?
Yes, you can enter interest rates from -50% to 100%. This allows you to simulate scenarios where assets decrease.
Editorial Review & References
- Reviewed by
- Toolsbase Editorial Team
- Last reviewed
References
Disclaimer
This tool assumes a constant annual rate of return and does not account for real-world factors such as market volatility, dividends, foreign-exchange fluctuations, fund management fees, transaction fees, or taxes on investment gains. All investments carry the risk of loss of principal. Before making significant investment decisions, please consult a qualified financial advisor, broker-dealer, or licensed financial professional.