Compound Interest Calculator
See how your money grows over time
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Calculate Compound Growth
Enter your investment details to see how compound interest grows your money over time.
Frequently Asked Questions
What is compound interest?
Compound interest is interest earned on both your original investment AND on the interest you have already earned. It is the reason a small amount invested early can grow to far more than a large amount invested later. Einstein reportedly called it the eighth wonder of the world.
Is 8% a realistic annual return?
The S&P 500 has averaged roughly 10% annually before inflation (about 7% after inflation) since 1926. An 8% assumption is moderate and commonly used for long-term planning. Actual returns vary year to year, and past performance does not guarantee future results.
How does compounding frequency affect returns?
More frequent compounding (monthly vs annually) increases returns slightly because interest starts earning interest sooner. The difference between monthly and annual compounding on a typical stock portfolio is small, but it adds up over decades.
Compound Interest Calculator
Calculate compound interest on any investment with monthly contributions. See year-by-year growth and the power of compounding over time.