Two acronyms, one letter apart, and a genuine amount of money riding on knowing which is which. APR appears on your credit card statement and your mortgage. APY appears on your savings account and your CDs. They look interchangeable — both are percentages, both are annual, both describe interest — but they measure different things, and treating one as the other will give you the wrong answer every time. This guide explains the difference in plain terms, shows the maths with a worked example, and points you to where each one actually shows up.
This is the second step in our borrowing series — if you haven’t yet, start with good debt vs bad debt to judge which debts are worth carrying, then read on for the rate that decides what they cost.
This is general educational information, not personalized financial advice. Details are current as of 2026.
The one-sentence difference
APY includes the effect of compounding. APR does not.
That’s the whole thing. Everything else follows from it.
APR — Annual Percentage Rate. The annualized cost of borrowing. It’s a simple rate: take the periodic rate and multiply it out across the year. For loans, US law also requires APR to fold in certain fees, so it reflects the true cost of credit rather than just the headline interest rate.
APY — Annual Percentage Yield. The annualized return on savings, with compounding already built in. If your bank pays interest monthly, and that interest starts earning its own interest, APY captures that. It answers: after a year, what will I actually have earned?
A rough memory aid: APR is what you pay, APY is what you yield. Not a perfect rule — but it holds for almost everything you’ll encounter as a consumer.
Side by side
| APR | APY | |
|---|---|---|
| Stands for | Annual Percentage Rate | Annual Percentage Yield |
| Measures | Cost of borrowing | Return on savings |
| Includes compounding? | No | Yes |
| Includes fees? | Yes, for loans (required by law) | No |
| You’ll see it on | Credit cards, mortgages, auto and personal loans | Savings accounts, CDs, money market accounts |
| Better for you when | Lower | Higher |
| Required by | Truth in Lending Act (Regulation Z) | Truth in Savings Act (Regulation DD) |
That last row is worth pausing on, because it explains why the two are defined differently.
Both disclosures exist to stop institutions flattering their own numbers. Lenders must show APR — which includes fees — so the cost of a loan can’t be hidden behind a low headline rate. Banks must show APY — which includes compounding — so the return on savings can’t be understated by quoting a bare nominal rate. In each case, the required figure is the one that’s most honest to you, not the one that looks best for them. That’s not an accident; it’s the point.
The worked example
Here’s where it becomes concrete. Take a 4.00% nominal rate and watch what happens depending on how often it compounds.
| Compounding frequency | Resulting APY | Earned on $10,000 |
|---|---|---|
| Annually | 4.0000% | $400.00 |
| Quarterly | 4.0604% | $406.04 |
| Monthly | 4.0742% | $407.42 |
| Daily | 4.0808% | $408.08 |
Same 4% nominal rate. Four different outcomes. That gap is compounding, and it’s exactly what APY exists to capture — so you can compare two accounts without having to know each bank’s compounding schedule.
Now the critical part, and the mistake almost everyone makes.
If a bank advertises 4.00% APY, the compounding is already in that number. So:
$10,000 at 4.00% APY earns exactly $400 in one year. Not $408.
The $408.08 figure in the table above comes from a 4% nominal rate compounded daily — which works out to a 4.0808% APY, not 4.00%. Applying daily compounding to an APY figure counts the compounding twice.
Run it the other way and it’s clearer still: to achieve exactly 4.00% APY with daily compounding, a bank needs a nominal rate of about 3.9223%. The advertised APY has already done that conversion for you.
The practical rule: when a rate is quoted as APY, your one-year interest is simply balance × APY. Nothing further.
Where you’ll see each
APY shows up on deposit accounts — the money you’re lending to the bank:
- High-yield savings accounts, where APY is the headline comparison figure. See our guide to the best high-yield savings accounts.
- Certificates of deposit, where APY is fixed for the term. See CD rates explained.
- Money market accounts, where APY is variable like savings.
APR shows up on credit — the money the bank is lending to you:
- Credit cards, where the APR is divided by 365 to produce a daily periodic rate. On a 20% APR, that’s about 0.0548% a day — roughly $16.44 on a $1,000 balance over a 30-day cycle. Our guide to calculating credit card APR works through this in full.
- Mortgages, where APR includes closing costs and so runs above the quoted note rate. On a $300,000 30-year mortgage at a 6.50% note rate with about $6,000 in financed costs, the effective APR is roughly 6.70% — which is precisely why comparing APRs rather than note rates is the honest way to shop.
- Auto and personal loans, where APR is again the fee-inclusive comparison figure.
Why the difference costs people money
Three concrete ways this bites:
Comparing a savings rate to a borrowing rate as if they’re equivalent. A 4.00% APY savings account and a 4.00% APR loan are not opposites that cancel out. The APY is your full return; the APR excludes compounding and, on a credit card, gets applied daily.
Shopping a mortgage on the note rate instead of the APR. Two lenders quoting 6.50% can have meaningfully different APRs once fees are counted. The APR is the comparison figure — that’s what it was created for.
Double-counting compounding on savings. Estimating your interest by compounding an APY is the single most common arithmetic error in personal finance, and it inflates your expectations by a small but persistent margin. Balance × APY. That’s it.
Frequently asked questions
What’s the simplest way to remember the difference? APY includes compounding; APR doesn’t. Or: APR is what you pay on borrowing, APY is what you earn on savings.
Can a savings account have both an APR and an APY? In practice you’ll only be quoted the APY, because that’s what US law requires for deposit accounts. A bank may have an underlying nominal rate, but the APY is the figure that matters — and it’s already the fully-compounded one.
Is a higher number always better? No, and this is where people slip. On APY, higher is better — you earn more. On APR, lower is better — you pay less. Same direction, opposite meaning.
Why is my mortgage APR higher than my interest rate? Because APR includes certain fees and closing costs alongside the interest. That’s deliberate: it stops a low advertised rate from masking expensive fees.
Does a credit card have an APY? Not one you’ll be quoted. Card interest is disclosed as APR, then applied daily. Because that daily application compounds, the effective annual cost of a carried balance is slightly higher than the stated APR.
If two accounts show the same APY, does compounding frequency still matter? No — and that’s exactly the point of APY. Two accounts at 4.00% APY return the same amount over a year, whether one compounds daily and the other monthly. The APY has already normalised for it.
How do I calculate my interest from an APY? For one year, multiply your balance by the APY. $10,000 at 4.50% APY earns $450. Don’t apply any further compounding.
The bottom line
APR and APY differ on one axis: APY has compounding baked in, APR does not. You’ll meet APY on savings accounts, CDs and money market accounts, where higher is better. You’ll meet APR on credit cards, mortgages and loans, where it also includes fees and lower is better. Both exist because US law requires the figure that’s most honest to you rather than most flattering to the institution. And if you take one practical habit from this: when a rate is quoted as APY, your annual interest is just balance × APY — nothing more.
Related reading: Go deeper on the borrowing side in how to calculate credit card APR, and on the savings side in best high-yield savings accounts and CD rates explained. And continue the borrowing series with good debt vs bad debt and debt avalanche vs snowball.
Sources
- Consumer Financial Protection Bureau (CFPB): https://www.consumerfinance.gov/
- Federal Deposit Insurance Corporation (FDIC): https://www.fdic.gov/
- Federal Reserve — Consumer credit and regulations: https://www.federalreserve.gov/
- FDIC — Truth in Savings (Regulation DD): https://www.fdic.gov/regulations/laws/rules/
- CFPB — Truth in Lending (Regulation Z): https://www.consumerfinance.gov/rules-policy/regulations/1026/
General educational information, not personalized financial advice. Regulations and rate conventions were current as of 2026. Always confirm the specific terms and disclosures provided by your bank or lender.
