💰 Finance
Compound Interest Calculator
See how your money grows over time with the power of compound interest.
$
%
yr
$
Future Value
$—
after 20 years at 7% annual return
Starting Amount
—
Contributions
—
Interest Earned
—
Growth over time
Principal
Contributions
Interest
| Year | Balance | Interest | Contributions |
|---|
How compound interest works
A = P(1 + r/n)^(nt) + PMT × [(1 + r/n)^(nt) − 1] / (r/n)
A = Final amount · P = Principal · r = Annual rate
n = Compounding periods/year · t = Years · PMT = Monthly contribution
A = Final amount · P = Principal · r = Annual rate
n = Compounding periods/year · t = Years · PMT = Monthly contribution
The Rule of 72
Divide 72 by your annual interest rate to find how many years it takes to double your money. At 7%, money doubles every ~10.3 years. At 10%, every ~7.2 years.