How to use the apy calculator
Enter the nominal annual rate and compounding frequency. APY expresses the one-year effect of compounding as a single annual percentage, which makes deposit products easier to compare on a like-for-like basis.
APY formula
When interest compounds more than once per year, APY is higher than the nominal rate because previously credited interest can earn additional interest.
Example: Priya compares a rate with its APY
Priya considers an account with a 5% nominal annual interest rate compounded monthly. Its modeled APY is [(1 + 0.05 ÷ 12)¹² − 1] × 100, or approximately 5.116%.
On an unchanged $10,000 deposit, that produces about $511.62 of interest over one year. If the account already quotes APY, do not compound that APY again as though it were a nominal rate.
APY vs. interest rate
An interest rate states the nominal rate used in the calculation, while annual percentage yield reflects the effect of compounding over a year. When interest is added to the balance and begins earning interest itself, APY can be higher than the stated nominal rate.
For deposit products, APY is useful because it creates a common annualized comparison. The actual dollars earned still depend on the balance, timing of deposits and withdrawals, account fees, and whether the rate changes.
Why compounding frequency changes APY
More frequent compounding credits interest to the balance more often. With the same nominal annual rate, that allows previously credited interest to participate in more compounding periods.
The difference can be small at modest rates, but the formula captures it precisely. Compare annual, monthly, and daily compounding with the same stated rate to see the effect without changing any other assumption.
How to compare savings accounts using APY
APY is one useful comparison point, but it is not the only account feature that matters. Minimum balances, fees, withdrawal restrictions, promotional periods, and variable-rate terms can change the real value of an account.
Use the calculator to understand the relationship between the nominal rate and effective yield. Use the bank's current disclosure for the actual APY and account conditions.
Assumptions and limitations
What the estimate assumes
Actual account earnings can depend on balance methods, fees, tiered rates, withdrawals, and when interest is credited.
Sources and reference material
APY Calculator FAQs
What is APY?
Annual percentage yield is an annualized measure of deposit interest that reflects the effect of compounding.
Is APY the same as an interest rate?
Not necessarily. A nominal interest rate states the rate before the compounding effect is annualized, while APY incorporates compounding over a one-year period.
Why is APY useful for savings accounts and CDs?
It provides a common annual measure that can make products with different compounding schedules easier to compare.
Does APY include account fees?
This calculator does not deduct fees. Review the account disclosure for fees, minimum-balance rules, and other conditions.
Can APY be higher than the interest rate?
Yes. When interest compounds more than once per year, the effective annual yield can be higher than the nominal annual rate because credited interest can earn additional interest.
Is APY guaranteed for a savings account?
Not necessarily. Many savings rates are variable. The calculator applies the entered rate consistently for the modeled year, while the actual account rate can change.
For educational comparison. Actual deposit earnings depend on the institution's account terms, balance method, fees, and crediting rules.