Compound Interest Calculator
See exactly how your investment grows with compounding. Add regular contributions and choose your compounding frequency.
Calculator Inputs
AFTER 20 YEARS
Total portfolio value
YEAR-BY-YEAR GROWTH
Frequently Asked Questions
What is compound interest?
Compound interest earns returns on both your principal and prior interest. At 7% annual return, $10,000 doubles in ~10 years without adding a single dollar.
How often should interest compound?
Monthly compounding earns slightly more than annual. For most equity investments, the difference between daily and monthly is under 0.1% annually.
What is a realistic stock market return?
The S&P 500 has returned ~10.5% annually (nominal) since 1957, roughly 7-8% after inflation. Dividend reinvestment (DRIP) boosts total returns significantly for income stocks.
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For educational purposes only. Not financial advice. Consult a qualified advisor before making investment decisions.