Compound Interest

Watch your money grow with an interactive line chart showing portfolio balance vs. total contributions over time. Enter an initial deposit, monthly contribution, annual rate, and years — the chart visualizes the power of compounding better than any table alone.

Compound interest drives retirement accounts, index funds, and long-term savings. Starting early with modest monthly deposits often beats investing larger sums later — the chart makes that gap obvious when you compare a 25-year-old vs. a 35-year-old starting with the same $200/month.

Adjust compounding frequency (annual, quarterly, monthly, daily) and compare conservative vs. aggressive return assumptions. Results show future value, total interest earned, and amount you contributed — so you see how much growth came from compounding vs. your own deposits.

Rule of 72 shortcut: divide 72 by your annual return to estimate years to double your money (e.g. 8% return ≈ 9 years). Our calculator gives exact figures including ongoing contributions, which the rule of 72 ignores.

Excellent shareable content for finance blogs and social — drives backlinks in the personal finance niche. Free, no account, runs entirely in your browser.