APY Calculator

What this calculator does

The APY Calculator estimates annual percentage yield, which expresses how much an interest-bearing balance can grow over one year when compounding is included. It is useful for comparing savings accounts, certificates of deposit, and other deposit products that compound at different frequencies.

How to use the calculator step by step

Enter the stated annual interest rate and select the compounding frequency used by the account. If the calculator includes a starting balance, enter it to estimate the resulting value. Compare APY rather than nominal rates when accounts compound differently.

How the calculation works

APY accounts for compounding during the year. A nominal rate compounded more frequently can produce an APY slightly higher than the stated rate because interest earned during earlier periods can itself earn interest.

Worked example and scenario testing

A 5% nominal annual rate compounded monthly produces an APY slightly above 5%. On a 10,000 balance, the difference may appear small over one year but becomes more noticeable over longer periods or larger balances.

How to interpret your result

APY is designed to make deposit yields easier to compare on a consistent annual basis. A higher APY generally means faster growth when fees, withdrawals, rate changes, and other conditions are equal.

Accuracy, assumptions, and limitations

Actual earnings can differ if the rate changes, fees apply, money is withdrawn, additional deposits are made, or the institution uses rules not represented by the calculator.

Common mistakes to avoid

Do not confuse APY with APR. APY includes the effect of compounding, while APR is commonly quoted without converting that effect into an annual yield.

Privacy and browser-based calculations

Only rate, balance, and compounding values are needed. Do not enter bank account numbers or login information.

Frequently asked questions