This lesson is general education about U.S. personal finance, not financial, tax or investment advice. Tax rules and limits change every year; check IRS.gov or a qualified professional for your situation.
What you’ll learn
- APY is the total interest a deposit earns in one year, including compounding, and federal rules require banks to disclose it so accounts can be compared.
- APY is always equal to or higher than the interest rate, because it adds in the effect of interest earning interest.
- The FDIC reported a national average savings rate of 0.39% in August 2025, so the gap between accounts can matter more than the size of your balance.
- A quoted APY does not include fees. On a small balance, a monthly maintenance fee can outweigh the interest, so read the fee schedule before opening an account.
- Compare APY to APY, check whether the rate is fixed or variable, and confirm the account is an FDIC-insured bank deposit.
When you compare savings accounts, you will see two percentages on the same page: an interest rate and an annual percentage yield, or APY. They look like the same number under different names. They are not. APY is the figure that tells you what a deposit actually earns in a year, and federal rules require banks to show it so accounts can be compared on equal terms. Learning to read it keeps a weak rate from dressing up as a strong one.
APY in One Sentence, and Why Banks Quote It
APY is the total interest you would earn on a deposit over one year, expressed as a single percentage, with compounding included. The Truth in Savings Act of 1991 defines it precisely: the total amount of interest that would be received on a $100 deposit over a 365-day period, based on the annual interest rate and the frequency of compounding.
That shared definition is the reason banks quote it. The act is carried out by Regulation DD, which requires banks to disclose the APY, the interest rate, fees and other account terms before you open an account, whenever you request them, and when the terms change. Because every institution must calculate APY with the same method, a 3% APY at one bank means exactly what a 3% APY at another means. The number exists to make comparison shopping possible.
It also matters after the account is open. If you set up an automatic savings transfer on payday, the APY is what goes to work on every dollar you park there.
Interest Rate vs. APY: What Compounding Adds
The interest rate is the base rate a bank pays on your balance. Compounding is what happens when earned interest is added back to the balance and starts earning interest of its own. APY folds both into one number, which is why it is always equal to or higher than the interest rate.
The gap depends on the rate and the compounding schedule. At low rates the difference is tiny: a 1% interest rate works out to an APY of about 1.005%. At higher rates it widens. A certificate of deposit paying 4.65% compounded monthly would be quoted as a 4.75% APY.
Compounding frequency can also outweigh a small difference in the headline number. One account might pay 5.10% interest compounded annually while a second pays 5.00% compounded daily. The second wins, because its APY works out to 5.12% against 5.10%. This is the same math that makes starting to save early more powerful than saving bigger amounts later: interest that earns interest does quiet work the whole time your money sits.
A Worked Example: $1,000 for One Year
This example is an illustration, not a quote from any bank. Because APY already includes compounding, the first year is simple multiplication: a deposit earns its APY in dollars.
| APY | Interest earned on $1,000 in one year |
|---|---|
| 0.39% | $3.90 |
| 1% | $10.00 |
| 3% | $30.00 |
| 5% | $50.00 |
The top row is not picked at random. In August 2025, the FDIC reported a national average savings rate of 0.39%, so an average-rate account earns about the price of a coffee on a $1,000 balance. The spread between that and a 5% APY is $46.10 on the same deposit, which is why the yield deserves a look before the money goes in. After the first year, compounding builds on the higher figure and the gap between accounts widens.
How Often Interest Posts, and Why Timing Matters
Savings accounts compound on different schedules: daily, weekly, monthly or quarterly. Each posting adds interest to the balance that future interest is calculated on, so more frequent compounding squeezes a slightly higher APY out of the same interest rate. That is why the daily-compounding account in the last section beat the annual one.
There is a second timing detail: compounding and crediting are not always the same thing. An account may calculate interest daily but deposit it into your balance only monthly or quarterly. Regulation DD sets rules for how banks handle that gap, including requiring the interest shown on your statement to reflect the amount actually paid. The practical takeaway is to check both the compounding frequency and the crediting schedule in the disclosure. The effect is small on a small balance and grows with the rate and the amount saved.
Variable Rates and What Makes Your APY Change
An APY can be fixed or variable. A fixed one, common on certificates of deposit, holds for a set term. A variable one, typical for regular savings accounts, can move while you hold the account. The account disclosure governs when and how the bank can change it.
So the APY you sign up for is not necessarily the APY you keep. If the terms change, federal rules require advance notice of adverse changes and entitle you to updated disclosures. Before opening an account, check from the disclosure whether the advertised yield is fixed or variable and what notice the bank must give if it drops.
Fees and Minimums That Can Eat the Whole Yield
Here is the catch the APY number does not show: it does not account for fees. An account can advertise a strong yield and still leave you behind if the charges attached to it outweigh the interest.
Run the arithmetic on your own expected balance. At a 1% APY, the $1,000 deposit in the table above earns $10 in a year. A monthly maintenance fee charged every month can add up to more than that over the same year, turning a small gain into a loss. The exact figures depend on the account, which is why the fee section of the disclosure deserves as much attention as the yield.
The truth in savings disclosure you receive when you open an account lists the APY, the interest rate, minimum-balance requirements and the fees. Banks must provide it on request and before an account is opened. Things worth checking in it:
- Minimum balance rules, and what happens if your balance drops below them.
- Monthly maintenance fees, and whether anything waives them.
- Withdrawal limits, which many savings accounts carry.
- Early withdrawal penalties, which apply to some accounts, such as holiday club accounts.
- Larger minimum deposits and minimum balances, which money market deposit accounts generally require.
One related trap: money market deposit accounts are bank deposits, but money market mutual funds are securities. Funds carry investment expenses and risk, and they are not insured by the FDIC. Two products can share a name and sit at the same institution while working very differently.
How to Compare Two Savings Offers Fairly
Put two offers side by side on the same terms:
- Compare APY to APY, never APY to interest rate. The interest rate ignores compounding, so it understates what you earn.
- Confirm whether each APY is fixed or variable, and what would make a variable one change.
- Check the balance required to earn the advertised APY, along with every fee that would apply at your expected balance.
- Note withdrawal restrictions, since some accounts limit how often money can come out.
- Confirm the account is an FDIC-insured bank deposit.
Try it
Ask for the truth in savings disclosure before you move money in. Banks must provide it on request and before an account opens, and it puts the APY, the rate, the minimums and the fees in one document.
Then do the dollar math yourself. Multiply your expected balance by each APY, subtract a year of fees, and compare what is left. A slightly lower APY with no monthly fee can beat a higher one whose charges cancel the interest.
Common questions
Is a higher interest rate always better than a lower one?
Not always. A 5.00% rate compounded daily produces a 5.12% APY, which beats a 5.10% rate compounded annually. Comparing APYs shows which account actually pays more.
Why is APY higher than the interest rate?
APY includes compounding, meaning earned interest is added back to your balance and begins earning interest itself. The more frequent the compounding and the higher the rate, the wider the gap between the two numbers.
Does the APY include account fees?
No. APY reflects only the interest earned on the balance. Minimum-balance requirements and monthly fees are listed separately in the truth in savings disclosure, and on a small balance they can outweigh the interest.
Can my savings account APY change?
Yes, if it is variable. Regular savings accounts often carry variable APYs that the bank can change, while certificates of deposit usually hold a fixed APY for their term. The account disclosure explains when the bank can change the rate and what notice it must give.