What Is APY? Annual Percentage Yield Explained With Examples

Editorial note: This guide is for general education, not individualized financial advice. We independently research every topic and cite our sources. Our editorial standards · How we make money.

When you compare savings accounts or CDs, the most important number on the page is the APY. It tells you exactly how much your money will earn in a year, including the extra growth from compounding. This short guide explains what APY is, how it is calculated and how to use it.

APY defined

Annual percentage yield (APY) is the percentage of interest you earn on a deposit over one year, including compounding. Under the Truth in Savings Act and its implementing rule, Regulation DD, banks and credit unions must disclose the APY on deposit accounts, calculated in a standard way. That standardization is what makes APY useful: you can compare different banks directly.

APY vs. interest rate

The interest rate (sometimes called the nominal rate) is the base rate before compounding. The APY adds the effect of earning interest on interest during the year.

If interest compounds more than once a year, the APY is higher than the interest rate:

The differences are small, which is why the stated rate itself matters much more than the compounding schedule.

The APY formula

APY = (1 + r/n)ⁿ − 1

• r = annual interest rate (decimal)
• n = compounding periods per year

For a 4.00% rate compounded monthly: (1 + 0.04/12)¹² − 1 = 0.0407, or 4.07%.

Using APY to estimate earnings

For a rough one-year estimate, multiply your balance by the APY:

• $5,000 × 4.00% APY ≈ $200 in a year
• $20,000 × 4.00% APY ≈ $800 in a year

This assumes the rate and balance stay the same. For regular deposits or multiple years, use our compound interest calculator. For CDs, the CD calculator works directly from APY.

APY vs. APR

A simple way to remember: APY is what the bank pays you; APR is what you pay the lender. Read what is APR? for the borrowing side.

Variable vs. fixed APY

• Savings and money market accounts usually have variable APYs that the bank can change at any time.
• Certificates of deposit have a fixed APY for the full term, as long as you do not withdraw early. See how CDs work.

When comparing variable-rate accounts, consider a bank’s history of keeping its rate competitive, not just a promotional number.

Watch for conditions

Some accounts advertise a high APY that applies only if you:

• Keep a minimum balance
• Receive direct deposit
• Make a certain number of debit card transactions
• Stay under a balance cap (with a lower rate above it)

Read the account disclosure to make sure you will actually earn the advertised APY.

APY in practice: comparing two accounts

Suppose you have $15,000 to set aside for a home down payment you plan to make in two years, and you are choosing between two options:

Illustrative rates only; they are not current offers.

Both accounts are federally insured and equally safe. The only difference is the yield — and over two years it is worth more than $1,100 on the same deposit. That is why checking the APY on money you keep in savings is one of the simplest financial wins available.

If the rate on a variable account falls halfway through, your actual earnings will be lower than the estimate. For a guaranteed figure over a set period, compare the APY on a CD of the same length.

How interest is actually credited

Most banks calculate interest daily on your balance and credit it to your account monthly. Once it is credited, it starts earning interest too — that is the compounding the APY reflects. Your monthly statement shows the interest paid, and many banks also show an annual percentage yield earned (APYE) for the statement period. If your balance changed during the month, or the bank adjusted its rate, the APYE will differ from the advertised APY.

Two practical points follow:

• Money deposited mid-month still earns interest for the days it is in the account.
• Withdrawing before interest is credited may mean you earn interest only for the days the money was there; it is not forfeited under standard savings terms, but check your account agreement.

Common APY misconceptions

“A higher APY always means a better account.” Not if it comes with a monthly fee, a low balance cap or conditions you won’t meet. Compare the APY you will actually earn.

“APY is guaranteed for a year.” Only on fixed-rate products like CDs. On savings and money market accounts, the bank can change the rate at any time, often with little notice.

“APY and APR mean the same thing.” They measure opposite sides of the ledger — one what you earn, the other what you pay — and APR does not include compounding.

“Compounding frequency matters most.” The difference between daily and monthly compounding at the same rate is a few cents or dollars. The rate itself matters far more.

The bottom line

APY is the most reliable way to compare what deposit accounts will earn. Look for a competitive APY at an FDIC- or NCUA-insured institution, check the conditions attached to it and remember that variable rates can change. Explore high-yield savings accounts and our banking hub to put the concept to work.

This guide is part of our Banking & Savings hub and our complete personal finance guide. Spot an error? Request a correction.