Open a savings account and the bank advertises an APY. Apply for a car loan or credit card and you see an APR. They sound like twins, they are both percentages, and they both describe interest over a year. So why do banks use two different terms, and which one actually tells you what you will earn or pay?
The short version: APR ignores compounding, while APY includes it. That single difference is why APY is almost always a little higher than the plain interest rate, and why comparing an APR to an APY directly can quietly mislead you. In this guide you will learn exactly how each number is calculated, see worked examples with real figures, and walk away knowing which one to compare when you are shopping for a savings account, a CD, or a loan.
The one-sentence difference
Here is the cleanest way to hold these two terms in your head:
- APR (Annual Percentage Rate) is the simple annual rate. It is mostly used for money you borrow and it does not, by itself, account for interest compounding on interest.
- APY (Annual Percentage Yield) is the effective annual rate. It is mostly used for money you earn and it bakes in the effect of compounding.
If you have read our explainer on simple vs. compound interest, this will feel familiar. APR is the simple-interest cousin; APY is the compound-interest cousin. Banks tend to quote whichever number looks friendliest: the higher APY on the savings products they want you to open, and the APR on loans (where a lower-sounding number is more attractive).
What is APY, and why is it usually higher?
APY, the annual percentage yield, answers a practical question: if I leave my money in this account for a full year, what percentage will it actually grow by? It captures the magic of compound interest by assuming the interest you earn gets added to your balance and then earns interest itself.
The more often an account compounds, the more APY pulls ahead of the stated rate. The formula that converts a nominal rate into APY is:
APY = (1 + r / n)^n - 1
where r is the nominal annual interest rate (as a decimal) and n is the number of compounding periods per year. Suppose a high-yield savings account states a 5% nominal rate that compounds monthly (n = 12):
APY = (1 + 0.05 / 12)^12 - 1 = 0.05116 = 5.12%
So a 5.00% rate becomes a 5.12% APY once monthly compounding is included. Compound the same rate daily and you get about 5.13%. The gap looks small, but it is real money, and it is why a savings account is required by law to advertise its APY rather than its bare rate. We dig deeper into how often that should happen in our guide to daily vs. monthly vs. annual compounding.
What is APR, and what it leaves out
APR, the annual percentage rate, is the headline number on loans and credit cards. In the simplest case it is just the nominal rate: a card with a 24% APR charges roughly 2% per month (24% divided by 12). Crucially, the basic APR does not show you the compounding that happens when unpaid interest is added to your balance.
That distinction matters most with credit cards, where interest typically compounds daily. A 24% APR card actually costs you closer to a 27% effective rate once daily compounding is layered on, if you carry a balance. We break that trap down in detail in how compound interest works against you on debt.
APR can also include fees
There is a second wrinkle worth knowing. For many loans, particularly mortgages, the law requires lenders to roll certain up-front costs (origination fees, points, some closing costs) into the APR. That is why a mortgage APR is often higher than the quoted interest rate even though APR usually ignores compounding. In that context, APR is doing the opposite job of APY: instead of revealing extra cost from compounding, it reveals extra cost from fees. The takeaway is that APR is a borrowing-cost number, and exactly what it bundles in depends on the product.
APR vs. APY at a glance
| Feature | APR | APY |
|---|---|---|
| Stands for | Annual Percentage Rate | Annual Percentage Yield |
| Mainly used for | Loans, credit cards, mortgages | Savings, CDs, money market accounts |
| Includes compounding? | No (simple rate) | Yes |
| May include fees? | Often, on loans | No |
| Which is higher for the same nominal rate? | Lower | Higher |
| Required disclosure law (U.S.) | Truth in Lending Act (Reg Z) | Truth in Savings Act (Reg DD) |
| Good news for you when it is... | Low | High |
A worked example: same 6% rate, two different stories
Imagine two products that both advertise a nominal 6% rate, compounding monthly. Watch how the framing flips depending on whether you are earning or borrowing.
If you are saving $10,000
The 6% nominal rate compounds monthly into a 6.17% APY. Over one year your $10,000 grows to about $10,617, which is $17 more than the $10,600 that a flat 6% would have given you. That extra $17 is compounding at work, and it is exactly what the APY is designed to reveal.
If you are borrowing $10,000
The same 6% on a loan is quoted as a 6% APR. If you only ever saw the APR you might assume your yearly cost is a clean $600. But because interest compounds on any unpaid balance, the effective cost creeps toward that same 6.17%. The lender shows you the lower-sounding 6% APR; the true cost behaves like the 6.17% APY.
Rule of thumb: when you are earning, you want the number that captures compounding (APY). When you are borrowing, you want to remember that compounding is working against you, so the real cost is usually a bit higher than the APR suggests.
Why mixing them up costs you money
The single most common mistake is comparing an APR against an APY as if they were the same unit. Picture two savings accounts:
- Account A advertises a 5.00% rate (nominal, no compounding shown).
- Account B advertises a 5.05% APY.
At a glance, B looks better. But if Account A's 5.00% compounds daily, its true APY is about 5.13%, which actually beats Account B. Always compare APY to APY for deposits and APR to APR for loans. Comparing across the two is apples to oranges. This is one of the slip-ups we flag in our roundup of common compound interest mistakes.
A quick way to sanity-check any rate
If a bank only gives you a nominal rate, you can estimate the APY yourself with the formula above, or just run the numbers through a free compound interest calculator to see the real one-year growth. For a rough mental shortcut on how fast money grows at a given yield, the Rule of 72 is handy: divide 72 by the APY to estimate the years it takes to double.
Where you will meet each number in real life
Knowing the territory helps you stay alert:
- Savings and CDs: APY. When evaluating high-yield savings accounts, the APY is the apples-to-apples figure across banks.
- Credit cards: APR, compounded daily. The effective cost is higher than the sticker APR if you carry a balance.
- Mortgages and auto loans: APR, often inflated above the note rate because fees are folded in.
- Investment returns: often quoted as an annualized yield or APY-style figure, especially when dividends are reinvested and compound over time.
Key takeaways
- APR is the simple annual rate; APY is the effective rate that includes compounding. That is the whole ballgame.
- For the same nominal rate, APY is always equal to or higher than APR, and the gap widens with more frequent compounding.
- Compare like with like: APY to APY for savings, APR to APR for loans. Never compare one against the other.
- On loans, APR can also bundle in fees, which is why a mortgage APR often exceeds its quoted interest rate.
- When in doubt, convert a nominal rate to its true yield using
APY = (1 + r / n)^n - 1or a calculator, and judge every account by what it really earns or costs over a year.
Master this one distinction and bank marketing loses a lot of its power over you. Whether you are growing savings or paying down debt, the number that includes compounding is the one that tells the truth.