What is the Compound Interest Calculator?
Project how an investment grows with compound interest and optional monthly contributions. Money decisions are easier when you can see the numbers. Our finance calculators use the same standard formulas banks and financial planners use — amortization, compound interest and present-value math — so you can compare options before you commit.
How to use the Compound Interest Calculator
- Enter your initial deposit, your monthly contribution, your annual interest rate, your years and the remaining fields.
- Results update automatically as you type; you can also press Calculate.
- Read the output: future value, total contributions, interest earned.
- Use the 📊 chart to see the result visually, then copy or share it.
Formula and method
Worked example
With initial deposit = $10,000, monthly contribution = $200, annual interest rate = 7 %, years = 15 years, compounding = Monthly, the Compound Interest Calculator returns future value: $91,881.93; total contributions: $46,000.00; interest earned: $45,881.93.
Tips for better results
- Compare at least two scenarios (for example, a 15- vs 30-year term) before deciding.
- Small rate differences compound: a 0.5% lower rate can save thousands over a long loan.
- Results are estimates; your lender’s fees, taxes and exact day-count rules may change the final figure.
⚠️ These results are for educational purposes and are not financial advice. Confirm figures with your lender or a licensed financial professional before making decisions.
Frequently asked questions
What does the Compound Interest Calculator do?
Project how an investment grows with compound interest and optional monthly contributions.
How is it calculated?
The Compound Interest Calculator uses this method: A = P(1 + r/n)^(nt) + monthly deposits compounded at the equivalent monthly rate.
Can you show an example?
With initial deposit = $10,000, monthly contribution = $200, annual interest rate = 7 %, years = 15 years, compounding = Monthly, the Compound Interest Calculator returns future value: $91,881.93; total contributions: $46,000.00; interest earned: $45,881.93.
Is the Compound Interest Calculator accurate?
It uses standard published formulas and is tested against known values, but results are estimates for guidance. These results are for educational purposes and are not financial advice. Confirm figures with your lender or a licensed financial professional before making decisions.
Is this tool free and private?
Yes — the Compound Interest Calculator is completely free with no sign-up, and it runs entirely in your browser, so the values you enter are never uploaded to our servers.
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