One of the easiest ways to calculate how compound interest will grow your funds is to estimate it using the Rule of 72. Divide 72 by the annual interest rate, or APY, offered.

That’s a $214 difference—in your favor—made possible by the power of compound interest. How to Calculate Interest Earned on a Savings Account.

The formula for calculating daily compound interest is A = P(1 + r/n)^nt. A is the amount of money you'll wind up with. P is the principal or initial deposit.