Free Online APY Calculator
Enter the nominal annual interest rate and how often it compounds. You get APY—the effective yearly yield after compounding—so you can compare savings products on equal terms.
APY is the effective yearly yield after compounding—not the same as a simple APR when interest posts more than once per year.
How APY is calculated
APY (annual percentage yield) is the real yearly return when interest compounds more than once per year. Formula: APY = (1 + r/n)n − 1, where r is the stated annual rate (as a decimal) and n is compounding periods per year.
APR is the stated rate without emphasizing compounding. When interest compounds monthly, APY is slightly higher than the nominal APR at the same quoted rate.
Use this for savings accounts, money market accounts, and CDs—not for loan APR comparisons unless you also account for fees.
How to use this calculator
- Enter the stated annual interest rate (nominal APR on the account).
- Choose how often interest compounds (daily, monthly, quarterly, etc.).
- Read APY—the effective annual yield—and the equivalent rate per compounding period.
- Try another frequency to see how compounding changes the true yearly return.
Worked examples
Sample numbers you can try in the calculator above. Your lender's quote may differ slightly.
High-yield savings (5% monthly)
Monthly compounding adds a small boost over the quoted 5% APR.
5.00% nominal · monthly compounding
APY: APY about 5.12%
CD quoted at 4.5% daily
Daily compounding is common on competitive CDs; APY is what you earn in a full year if the rate holds.
4.50% nominal · daily compounding
APY: APY about 4.60%
Quarterly vs annual
More frequent compounding raises effective yield at the same nominal rate.
3% nominal · quarterly vs once per year
APY: Quarterly APY slightly higher than 3%
Comparing two offers
The account with higher APY pays more over a year, even if the headline APR looks similar.
Bank A 4.8% monthly · Bank B 4.85% annually
APY: Calculate both APYs side by side
Frequently asked questions about the aPY Calculator
What is APY?
Annual percentage yield is the effective yearly return after compounding. It reflects interest on interest within the year.
APY vs APR?
APR is the stated yearly rate; APY is usually higher when compounding happens more than once per year. For deposits, compare APY.
Why does compounding raise APY?
Each period, you earn interest on prior interest. More periods per year mean more growth at the same nominal rate.
Is APY guaranteed?
Variable savings APY can change. Fixed-term CDs may lock a rate for the term—check the product disclosure.