APY vs Interest Rate: Why the Numbers Differ on Savings Accounts

A savings account can display a 5% interest rate and an APY slightly above 5%. That is not necessarily a typo. The interest rate describes the stated annual rate used in the account's interest calculation. APY, short for annual percentage yield, expresses how much interest the account would earn over a year under specified assumptions, including compounding. When interest remains in the account and starts earning more interest, the APY can exceed the stated rate.

The two figures serve different purposes. Use the account's terms to understand how interest is calculated and credited. Use APY to compare deposit offers on a more consistent annual basis. Neither figure tells you how much you personally will earn if you change your balance, pay fees or hold a variable-rate account whose rate moves during the year.

What the interest rate tells you

For a deposit account, a stated interest rate identifies the annual rate the institution applies under its disclosed balance and timing method. A 5% annual rate does not mean the account earns 5% every month. In a simple monthly-compounding model, the periodic rate is 0.05 divided by 12, about 0.4167% per month. Interest is then calculated on the eligible balance for that period.

Real account calculations may use a daily or average daily balance, and the institution may credit interest on a different schedule from its calculation schedule. The disclosure should explain the method. The CFPB's deposit-account disclosure rule requires information about the frequency of compounding and crediting, the balance computation method and when interest begins to accrue on noncash deposits. Those details are more useful than guessing from a headline rate.

What APY tells you

APY is an annualized deposit yield that accounts for interest earned under the disclosure's assumptions. The CFPB's APY calculation guidance states that APY measures interest paid based on the interest rate and compounding frequency. For a typical savings account without a maturity date, the disclosure calculation assumes a 365-day term. It generally assumes principal and interest remain on deposit with no other transactions during that term.

That makes APY useful for comparing accounts, but not a promise that a variable rate will stay unchanged. If the rate changes, you add or remove money, or the account charges a fee, your actual dollar result can differ from a one-year APY illustration. Check any minimum-balance or tiered-rate conditions too. A yield available only above a threshold may not apply to your planned balance.

A checked example at 5% nominal interest

Imagine $10,000 earns a fixed 5% nominal annual rate with monthly compounding for one year. Assume no deposits, withdrawals, taxes or fees. The model is $10,000 × (1 + 0.05/12)^12. The ending balance is about $10,511.62, so interest is $511.62. Relative to the $10,000 starting balance, that is about 5.116% growth over the year. In this simplified case, the effective annual yield is about 5.116%, while the nominal annual rate is 5%.

Figure	Meaning in this example	Value
Interest rate	Nominal annual rate used to set each monthly rate	5.00%
Monthly periodic rate	5% divided by 12	About 0.4167%
Effective one-year yield	Growth after monthly compounding	About 5.116%
Interest on $10,000	Ending balance less starting balance	About $511.62

Do not reverse the labels. If an account advertises a 5% APY with monthly compounding, the monthly periodic rate implied by that fixed model is about 0.4074%, not 5% divided by 12. A $10,000 balance under the model earns about $500 over the year. Putting 5% APY into a calculator that asks for a nominal annual rate and selecting monthly compounding would count the compounding effect twice.

Why your statement may show another yield

Deposit statements can show an “APY earned” for a specific statement period. It reflects the interest actually earned in that period relative to the relevant average daily balance, annualized under the rule. It can differ from the advertised APY if your balance changed, rates changed or the statement period and compounding schedule interact. A one-month statement is not simply one twelfth of the annual illustration.

Check the statement's dates, interest amount and balance before assuming a discrepancy. A deposit made halfway through the month cannot earn for days before it arrived. If the difference remains unexplained, ask the institution which balance method, day count, rate tier and crediting date it used. The CFPB guidance distinguishes the advertised APY calculation from APY earned on periodic statements.

APY is not APR

APY usually appears with deposit products and expresses yield earned. APR, annual percentage rate, is commonly used for borrowing and can include charges beyond the loan's interest rate. Swapping one abbreviation for the other changes the question. Our APR versus interest rate guide discusses borrowing costs. This article is about deposit-account earnings.

A bank may also show an APY on a certificate of deposit. Its term, interest payout and early-withdrawal conditions still matter. Our CD compounding guide explains why paying interest out can change the result you keep inside the CD.

How to compare two savings accounts

Put each offer's APY, rate type, minimum balance, fees and withdrawal terms side by side. Check when rates can change and whether a promotional yield lasts for a limited period. Then estimate dollars using your realistic balance and deposit schedule. If the offers have nearly identical APYs, fees or access restrictions may matter more than a small difference in compounding frequency.

ToolNimbly's compound interest calculator asks for a nominal annual rate and a compounding frequency. Use it to explore a fixed-rate illustration and recurring deposits, not to recreate a bank's exact APY disclosure or statement. The calculator excludes fees, taxes, inflation and changing rates. Its daily versus monthly guide shows how frequency affects the same nominal rate.

The practical rule is to compare APY with APY across deposit offers, then read the account terms. Use the stated interest rate when a calculation explicitly asks for that rate. Keep the label attached to the number, and the apparent contradiction between the two figures largely disappears.