Simulate how your investments grow exponentially over time. Support for initial principal, regular monthly additions, custom compounding frequencies, and annual return rates.
Enter your values, then select Calculate Now
Calculates Future Value (FV): FV = P * (1 + r/n)^(n*t) + PMT * [((1 + r/n)^(n*t) - 1) / (r/n)], where P = principal, PMT = regular monthly deposit, r = annual interest rate, n = compound frequency per year, and t = years. Total Contributions = P + (PMT * 12 * t). Total Interest = FV - Total Contributions.
Compound interest contributed 62.1% of the final wealth ($213k), far surpassing the actual money you deposited out of pocket ($130k).
Enter your starting investment principal balance.
Input the regular monthly cash addition you plan to deposit.
Specify your estimated annual rate of return (e.g. 7% to 10% for broad stock market indexes).
Select your investment horizon in years.
Choose your compounding frequency (monthly is typical for mutual funds and ETFs).
Review the interactive growth breakdown, total interest vs principal split, and year-by-year table.
The Rule of 72 estimates how many years it takes for an investment to double: divide 72 by the annual rate of return. For example, at an 8% return, your money doubles approximately every 9 years (72 / 8 = 9).
Historically, the S&P 500 has delivered an average annual return of approximately 10% before inflation (or roughly 7% after inflation) over the past century.
Yes! High-interest debt (like credit cards at 24% APR) compounds against you exponentially, which is why paying off credit cards must precede aggressive investing.
More frequent compounding generates slightly higher returns because interest begins earning interest sooner, though the difference between daily and monthly compounding on modest sums is relatively small.
No. In tax-advantaged accounts like traditional or Roth IRAs and 401(k)s, dividends and capital gains compound 100% tax-free until withdrawal (or completely tax-free forever in a Roth).
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