APR vs APY: The Two Interest Rates Banks Hope You Confuse

Open any bank's website: the savings page shouts APY while the loan page whispers APR. Same institution, same mathematics — different number chosen for each audience. It's not fraud; both figures are honest. But knowing which is which, and how to convert between them, is the difference between comparing offers and being compared to.

The Definitions, Minus the Jargon

• APR (Annual Percentage Rate): the yearly rate before counting how often interest compounds within the year. The "sticker" rate.
• APY (Annual Percentage Yield): what you actually earn or pay over a year including intra-year compounding. The "real outcome" rate.

The bridge between them: APY = (1 + APR/n)ⁿ − 1, where n is compounding periods per year. Whenever compounding happens more than once a year, APY > APR — and the gap grows with both the rate and the frequency.

How Big Is the Gap, Really?

Two lessons hide in this table. First, at savings-account rates the monthly-vs-daily distinction is nearly worthless — chase the rate, not the frequency. Second, at credit-card rates the gap is enormous: your "24%" card effectively charges over 27% on carried balances. Convert any pair yourself in the Interest Rate Calculator.

Why Banks Advertise Each Where They Do

Marketing prefers the bigger number for things paid to you and the smaller for things paid by you:

• Savings/CDs → APY (larger, looks generous — and US regulation actually requires APY disclosure here, helpfully).
• Loans/cards → APR (smaller, looks cheap — also the legally mandated disclosure, which at least standardizes comparison).

The trap isn't either number — it's comparing one bank's APY against another's APR as if they were the same species.

Real Comparisons, Done Right

Savings: the "smaller" number can win

Bank A: 5.90% APR compounded daily → APY 6.08%. Bank B: 6.00% APR compounded annually → APY 6.00%. A wins despite the smaller headline. On $50,000 over five years, that's roughly $186 of difference — found only by converting both to APY.

Loans: fees hide inside APR

US loan APR must fold in certain mandatory fees, which is why a "6.5% + $4,000 in points" mortgage can disclose a 6.8% APR. When comparing mortgages, compare APRs at the same term — and see our guide on how much house you can afford before rate-shopping at all.

The monthly-rate trap

"Only 2% per month" annualizes to (1.02)¹² − 1 = 26.8% per year — not 24%. Any rate quoted per month deserves immediate conversion; it's the oldest small-print trick in lending.

Three Rules to Keep

1. Savings: compare APY to APY. It's the only number that includes what compounding gives you.
2. Loans: compare APR to APR at equal terms. It's the only number that includes what fees cost you.
3. Anything quoted monthly or weekly: annualize before judging. (1 + rate)^periods − 1, or let the calculator do it.

Worked Scenario: Tomás Borrows $15,000 Three Ways

Tomás needs $15,000 over three years and collects three quotes, each priced in a different dialect. Converting all of them to the same annual number takes about ninety seconds and changes his answer entirely.

What the conversion exposes:

• The lowest monthly payment is not the cheapest loan. Offer B costs $10 less each month than Offer A and $397 more overall, because $750 of the money he "borrowed" was handed straight back to the lender at signing.
• A one-time fee behaves like a permanent rate. That $750 does not add 5% to the price; spread across 36 payments it adds about 3.5 points of APR — which is why the fee-inclusive figure exists at all.
• "1.5% a month" is 18% a year nominal and 19.6% effective, not the small number it sounds like. Any rate quoted per month should be multiplied by 12 before it is allowed near a decision.

The variation worth noticing: if Tomás takes Offer B over 12 months instead of 36, the same $750 fee is spread over a third as much time, and its true APR climbs from 12.0% to roughly 18% — level with the retail offer he laughed at. Fees get more expensive as terms get shorter, which is the exact opposite of most people's intuition. Price your own quotes in the Loan Calculator and convert any odd rate in the Interest Rate Calculator.

Common Mistakes When Comparing Rates

1. Shopping by monthly payment. Payment size is a function of term as much as price, so lenders can lower it by stretching the loan. A $30,000 car at 7% over seven years costs $8,031 in interest; at 7.5% over four years it costs $4,815 — the "worse" rate is $3,216 cheaper (the 20/4/10 rule exists for exactly this reason).
2. Believing "0% APR for 12 months" means no interest. Many retail promotions use deferred interest: leave $1 unpaid on day 366 and the full rate is charged retroactively from the purchase date. Read whether the offer says "deferred interest" or "no interest accrues."
3. Signing up for a teaser APY and leaving the money there. A 6% promotional APY for three months that reverts to 0.5% blends out to about 1.9% over a full year. Compare the go-to rate, not the headline, unless you intend to move the money on schedule.
4. Comparing savings APY to inflation before tax. A 4.5% APY at a 22% marginal rate is 3.5% after tax, which loses purchasing power against 4% inflation. Judge savings on the after-tax, after-inflation number (see why money shrinks).
5. Studying a card's compounding frequency while ignoring the grace period. Pay a credit card in full and the APR is irrelevant, because no interest is charged. Carry any balance and you forfeit the grace period, so new purchases start accruing from the day of the swipe rather than the due date.
6. Assuming APR captures every cost. Mortgage APR folds in most mandatory loan fees, but credit card APR excludes annual fees, cash-advance fees, and foreign transaction charges entirely. A card at 19.9% APR with a $95 annual fee is not a 19.9% product for anyone carrying a small balance.

The Bottom Line

APR is the ingredient; APY is the meal. Banks will always serve whichever looks better on the menu — your job is a five-second conversion so every offer competes on the same field. For what compounding does to these rates over decades rather than years, our compound interest guide and the Compound Interest Calculator finish the story.