Compound Interest Calculator
Compute final balance and total interest with a year-by-year growth chart vs simple interest.
For reference only — not investment advice.
What is Compound Interest Calculator
Watch compound growth do its quiet work: enter principal, annual rate, years and a compounding frequency — yearly, quarterly or monthly — to get the final balance and total interest earned. A stacked year-by-year chart shows interest overtaking principal, with simple interest alongside for contrast.
How to use Compound Interest Calculator
- Enter principal, annual rate and years; choose compounding frequency
- Compare compound vs simple interest totals
- Hover the bars for year-by-year amounts
Frequently asked questions
What is the Rule of 72?
Divide 72 by your annual rate to estimate years to double your money. At 6% per year, money doubles in about 12 years.
What is the compound interest formula?
A = P(1 + r/n)^(nt): $10,000 at 5% compounded monthly for 10 years grows to about $16,470, versus $15,000 with simple interest.
Does more frequent compounding matter much?
A little. Monthly beats yearly by a fraction of a percent at the same nominal rate — meaningful over decades, negligible over a year.
Is Compound Interest Calculator free?
Compound Interest Calculator is completely free — open the page and use every feature with no hidden charges.
Do I need to download or install Compound Interest Calculator?
No download or installation is needed. It is an online tool that runs in the browser on your phone, tablet and computer.
Do I need an account to use Compound Interest Calculator?
No. Use the tool right away — no account or sign-in required.
Does Compound Interest Calculator work on mobile?
Yes. The page is fully responsive and works on phones, tablets and desktop browsers.