Compound Interest Calculator
Determine how your principal deposits and monthly contributions grow over time with compounding interest.
The Power of Compound Growth
Compound interest is interest calculated on both the initial principal amount and all accumulated interest from previous periods.
1. Standard Formula
The basic formula without recurring deposits:
Where P = principal, r = rate, n = compounding frequency, and t = years.
2. The "Rule of 72"
A quick mental math shortcut to estimate how many years it takes to double your money:
At a 7% interest rate, your money doubles in approximately 10.2 years (72 / 7).
3. Impact of Frequency
More frequent compounding intervals (e.g., daily vs. annually) yield higher total returns over time because interest accrues on smaller intervals.