Compound Interest Calculator
Calculate how your investments grow over time with the power of compounding.
How compound interest works
Compound interest is one of the most powerful forces in personal finance...
The formula is straightforward: A = P(1 + r/n)^(nt)...
The power of time
An investor who puts $5,000/year...
What return rate to expect
The S&P 500 has historically returned...
Why monthly contributions matter
Your monthly contribution is often more impactful...
Compound interest vs. simple interest
Simple interest pays a fixed percentage...
Frequently asked questions
Compound interest is interest calculated on both the initial principal and accumulated interest.
More frequent compounding yields slightly more.
S&P 500 has historically returned ~10% annually.
$10,000 plus $500/month at 7% for 30 years grows to ~$567,000.
Divide 72 by your annual return rate to estimate doubling time.