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Compound Interest Calculator

Watch your money grow exponentially

Investment Parameters
Your Future Wealth
Final Amount
$695K
That's 69x your initial investment
Total Contributions$190K
Interest Earned$505K
Return on contributions266%
Wealth Multiplier3.7x
Every dollar becomes$3.66
Growth Visualization
$0$174K$347K$521K$695K0.0y7.5y15.0y22.5y30.0y
Your ContributionsInterest Earned

Compound Interest Magic

  • Often attributed to Einstein: compound interest is "the eighth wonder of the world"
  • The "Rule of 72": Your money doubles every 72 ÷ interest rate years
  • Starting early is more powerful than contributing more later
  • At 7%, your money doubles every ~10 years

How it calculates

The annual rate is split into twelve monthly rates, or 52 weekly ones in weekly mode. Each period the contribution is added first, then that period's interest is credited on the whole balance. The result is a projection at a constant rate, before taxes, fees and inflation.

$10,000 plus $500 a month at 7 % for 30 years → about $695,000, of which $190,000 are your own payments

Crypto turbo mode

The switch at the top runs the same arithmetic with the rate per week or per month instead of per year. It is a joke, not a forecast.