Calculate compound interest growth. Fast, accurate, and completely free.
A = Final Amount
P = Principal Amount
r = Annual interest rate decimal
n = Compounding frequency per year
t = Time in years
Enter your starting Initial Principal capital.
Input the Annual Interest Rate (%).
Specify the number of years you plan to let the wealth grow.
Select the Compounding Interval (Daily compounding delivers the highest returns).
Albert Einstein famously referred to compound interest as the "eighth wonder of the world." Unlike simple interest, which only calculates returns on your initial capital, compound interest calculates interest on your principal plus all previously accumulated interest. This creates an exponential growth curve over time.
The Rule of 72 is a quick shortcut to estimate when your investment will double. Divide 72 by your annual interest rate (e.g., 72 / 8% = 9 years to double).
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