Compound Interest Calculator
Visualize how your money grows over time when you reinvest your earnings.
The S&P 500 averages 7% to 10% historically.
Total Future Value
$345,742
Total Invested
$130,000
Compound Interest Earned
+$215,742
Wealth Growth Over Time
Frequently Asked Questions
What is compound interest?
Compound interest is the interest you earn on both your original money and on the interest you keep accumulating. It is often called the "eighth wonder of the world" because it makes your wealth grow exponentially over time.
How is this different from simple interest?
Simple interest is only calculated on your initial principal. For example, 10% simple interest on $100 will always pay exactly $10 every year. Compound interest means next year you earn 10% on $110, paying $11. Over 30 years, the difference is massive.
What interest rate should I use?
Historically, the U.S. stock market (S&P 500) has returned roughly 7% to 10% per year on average over long periods. A high-yield savings account might offer 4% to 5%. Use conservative estimates for planning.