APR vs APY: The Difference That Costs You Money

Banks advertise savings accounts with APY and loans with APR — and that's not an accident. The two acronyms measure interest in different ways, and each one makes the bank's side of the deal look better. Understanding the difference takes five minutes and will save you money every time you compare a savings account, credit card, or loan for the rest of your life.

APR and APY, Defined

APR (Annual Percentage Rate) is the simple annual interest rate — the periodic rate multiplied by the number of periods per year. It does not account for compounding. A credit card that charges 2% per month has a 24% APR, even though your actual yearly cost is higher.

APY (Annual Percentage Yield) is the effective annual rate — what you actually earn or pay after compounding is included. The formula is APY = (1 + APR/n)ⁿ − 1, where n is the number of compounding periods per year. Because compounding only ever adds interest-on-interest, APY is always equal to or higher than APR for the same underlying rate.

The Same 5% Rate, Four Different Results

Here's what a 5% APR actually yields at different compounding frequencies:

On a savings account the differences look small — about $13 a year on $10,000 between annual and daily compounding. But two lessons hide in this table. First, frequency matters less than the rate itself: chasing daily compounding at 5% instead of monthly at 5% earns you almost nothing, while finding a 5.5% account instead of a 5% one earns you $50. Second, on debt, the same math works against you at much bigger scales. Convert any rate in either direction with our APR to APY Calculator.

Why Banks Choose the Number They Show You

For savings products, banks advertise APY because it's the bigger number — a 5% APR account compounding daily gets marketed as "5.13% APY." For loans and credit cards, they advertise APR because it's the smaller one. A credit card with a 24% APR compounding monthly actually costs 26.82% per year if you carry the balance. At 20% APR with daily compounding — common for credit cards — the true annual cost is 22.13%.

In the U.S., regulation partially protects you: the Truth in Savings Act requires banks to disclose APY on deposit accounts, and the Truth in Lending Act requires APR disclosure on loans. The trap is comparing one product's APR against another's APY — always convert both to the same measure before choosing.

What This Means for Your Credit Card

Credit card interest is where the APR/APY gap costs real money. Carry a $5,000 balance at 24% APR and the "24%" suggests $1,200 a year in interest. But because interest compounds monthly on the growing balance, the effective cost is closer to $1,341 — and that's assuming the balance doesn't grow. Minimum payments are calibrated so that most of your payment services interest, not principal, which is why a $5,000 balance can take more than a decade to clear at minimums. See your real payoff timeline — and how much a modest extra payment shortens it — with our Credit Card Payoff Calculator.

Quick Rules for Comparing Rates

• Savings accounts and CDs: compare APY to APY. It's the number that reflects what actually lands in your account.
• Loans and mortgages: compare APR to APR — and note that a loan's advertised APR usually includes mandatory fees, which is why it can be higher than the note rate.
• Credit cards: the advertised APR understates the true cost if you carry a balance; convert to APY to see the real annual price of the debt.
• Mixed comparisons: if one product quotes APR and the other APY, convert before comparing — a 5.05% APR compounding daily beats a 5.10% APY.

The Bottom Line

APR is the sticker rate; APY is what actually happens to your money once compounding does its work. The gap between them is small on savings and painful on debt — which is exactly why each side of the banking industry shows you the number that flatters its product. Compare like with like, let the compounding math work for you in savings, and starve it on the debt side by paying more than the minimum. To see compounding working in your favor over decades, try our Compound Interest Calculator.