Compound Interest Calculator
See how your money grows over time. This calculator shows the power of compound interest with monthly contributions, different compounding frequencies, and inflation adjustment.
Investment Return Calculator
Project compound growth with regular contributions
Uses future value formula: FV = P(1+r/n)^(nt) + PMT×[((1+r/n)^(nt)-1)/(r/n)]. Contributions are assumed at the end of each period. Returns are not guaranteed and do not account for taxes or fees.
Frequently Asked Questions
How does compound interest work?+
Compound interest earns returns on your original investment PLUS previous returns. Example: $10,000 at 7% compounded annually becomes $10,700 after year 1, then $11,449 after year 2 (interest on $10,700). Over 30 years, $10,000 grows to $76,123 without adding a penny.
How much will $10,000 grow in 10 years?+
At 7% annual return (stock market average): $19,672. At 4% (savings account): $14,802. At 10% (aggressive investing): $25,937. Adding $500/month: $10k + contributions = $103,000+ at 7%. The monthly contributions matter more than the initial amount.
What is the rule of 72?+
The Rule of 72 estimates how long it takes your money to double: 72 ÷ interest rate = years to double. At 7%: doubles in ~10 years. At 10%: doubles in ~7.2 years. At 4%: doubles in ~18 years. It's a quick mental math trick for investment planning.
How does compound interest work?
Compound interest earns returns on your original investment PLUS previous returns. Example: $10,000 at 7% compounded annually becomes $10,700 after year 1, then $11,449 after year 2 (interest on $10,700). Over 30 years, $10,000 grows to $76,123 without adding a penny.