Compound Interest Calculator
Visualize the incredible power of compound interest and see how your money grows exponentially over time with consistent contributions.
Investment Details
Set your starting point and contribution plan.
Your initial investment
Amount invested each month
Average annual rate of return
How long you plan to invest
Final Balance
$691,150
Total Contributions
$190,000
Total Interest Earned
$501,150
73% of total
Growth Over Time
How Compound Interest Works
Compound interest is interest earned on both your original principal and on the interest that has already been added. This creates an exponential growth curve that accelerates over time, often called the eighth wonder of the world.
The Rule of 72
A quick way to estimate how long it takes to double your money: divide 72 by your annual return rate. At 7%, your money doubles approximately every 10.3 years.
Why Starting Early Matters
The earlier you start investing, the more time compound interest has to work. Even small amounts invested consistently over decades can grow to substantial sums. Time in the market beats timing the market.