Calculate annual percentage yield (APY) from a nominal interest rate and compounding frequency. Add a starting balance to estimate one year of savings interest and the ending balance.
Compound interest, APY, future value and long-term savings-growth calculations.
Enter the nominal annual interest rate and how often interest compounds. The calculator converts that rate to annual percentage yield. Add an optional starting balance to estimate one year of interest and the ending balance.
Here, r is the nominal annual rate as a decimal and n is the number of compounding periods per year.
APY includes compounding, so it can be higher than the nominal stated rate when interest compounds more than once per year.
APY is commonly used to compare savings accounts and certificates of deposit because it reflects compounding over a year. If you are estimating a specific CD balance at maturity, use the CD Calculator.
Estimate a certificate of deposit with the CD calculator, project a future balance with the future value calculator, or compare methods in compound vs. simple interest.
At a 4.8% nominal annual rate compounded monthly, APY = (1 + 0.048/12)^12 − 1, or about 4.907%. An initial $15,000 balance earns about $736 in one year before taxes if the rate stays unchanged.
What to check: A stated APY already includes compounding; do not compound an APY again. This calculation assumes the stated rate remains unchanged and excludes withdrawals, fees, and taxes.
Compare with the Compound Interest calculator when that better matches the question you are trying to answer.
With the same positive nominal rate, more frequent compounding generally increases APY slightly.
See how formulas, sources and limitations are handled across ERICH Calculators.