APR vs APY: What the Difference Means

Two rates describe almost every financial product in the United States, they are spelled almost identically, and they mean genuinely different things. APR vs APY is not pedantry — the gap between them is precisely the part of the cost that advertising tends to leave out.

The short version: APY accounts for compounding, APR does not. Which one gets printed in large type depends entirely on which makes the offer look better.

What each one actually measures

APR — Annual Percentage Rate. A simple annualised rate. Take the periodic rate and multiply by the number of periods in a year. A card charging 1.5% a month has an 18% APR. No compounding is assumed in the number itself. For loans, US regulation also requires APR to fold in certain fees, which is what makes it useful for comparing mortgages.

APY — Annual Percentage Yield. The rate you actually end up with after compounding is applied:

APY = (1 + r/n)^n − 1

Where r is the nominal annual rate and n is compounding periods per year. That same 18% APR, compounded monthly, is:

(1 + 0.18/12)^12 − 1 = 0.1956 → 19.56% APY

The extra 1.56 points is not a fee. It is interest charged on interest that had already been added to the balance — the mechanism described in how compound interest works.

APR vs APY: which one gets advertised

The pattern is consistent once you notice it:

Product	Usually advertised as	Why
Savings account, CD	APY	Compounding makes the number bigger
Credit card	APR	Compounding makes the number bigger
Mortgage, auto loan	APR	Legally required, and it includes fees

Nobody is lying. A savings account genuinely pays its APY, and a card genuinely charges its APR. But when you are earning, the higher number flatters the offer; when you are paying, the lower number does. That asymmetry is why APR vs APY is worth ten seconds of attention on every product page you read.

The practical rule: compare like with like. Never put a savings APY next to a loan APR and conclude anything.

How big is the gap in practice

The spread widens as the rate rises, because compounding has more to work with:

Nominal rate (APR)	APY, compounded monthly	Gap
2%	2.02%	0.02 pts
6%	6.17%	0.17 pts
12%	12.68%	0.68 pts
24%	26.82%	2.82 pts

At savings-account rates the distinction is nearly academic. At credit card rates it is very real — a 24% APR card behaves like a 26.8% one if you carry a balance and never pay it down. On a $6,000 balance, that difference is about $170 a year of pure arithmetic. The credit card payoff calculator shows what a given monthly payment actually retires.

Where APR gets complicated: fees

For mortgages, APR is doing a second job. Federal disclosure rules require it to include points, origination charges and certain other costs, spread across the life of the loan. That is why a mortgage quote shows a lower interest rate and a slightly higher APR — the difference is the fees.

This makes APR the better comparison tool between two mortgage offers, with one sharp caveat: the spreading assumes you keep the loan for its full term. Pay it off or refinance in year six and you absorbed those fees over six years, not thirty, so your effective cost was higher than the quoted APR implied. The refinance calculator is built around exactly this break-even question, and how mortgage payments are calculated covers the underlying payment math.

The traps worth knowing

Introductory rates. A 0% APR promotional period is a real rate for a fixed window. What matters is the go-to rate afterwards and, on some deferred-interest offers, whether interest accrues in the background and lands retroactively if the balance is not cleared in time. Read that clause specifically.

Daily periodic rate. Most US card issuers compound daily and bill monthly. The APR is divided by 365 and applied each day, which is why the APY on a card is slightly higher than a monthly-compounding calculation suggests.

Grace periods. Pay the statement balance in full each month and a typical card charges nothing at all. In that case APR vs APY is irrelevant to you — the rate only starts mattering when a balance carries.

"Up to" yields. A headline APY sometimes applies only to a balance tier or requires direct deposits and a minimum number of debit transactions. The rate on the rest of the money is usually far lower.

Putting the numbers to work

If you are saving, what matters is the APY plus how long the money compounds — run it through the compound interest calculator, or use the savings goal calculator to solve for the monthly deposit that hits a target by a specific date. If you are borrowing, the auto loan calculator and student loan payoff calculator show total interest, which is the figure that actually leaves your account.

One habit covers most of it: whenever you see a rate, ask which of the two it is, and whether the party showing it to you benefits from that choice.

For official definitions, the Federal Reserve explains APR under Regulation Z, and the FDIC publishes the deposit-side rules that govern how APY must be advertised on savings products.