APR vs interest rate: the actual difference

Two numbers used interchangeably that mean different things — except on credit cards, where they genuinely are the same. Here is when each one matters.

The short answer

Your interest rate is the cost of borrowing the money. Your APR is the cost of borrowing plus certain required fees, expressed as a yearly percentage. APR is designed to be the more complete number — which is exactly why lenders advertise whichever one looks better.

On loans and mortgages

Here the distinction matters most. A mortgage advertised at a 6.5% interest rate might carry a 6.7% APR once origination fees and points are folded in. The interest rate determines your monthly payment; the APR is a better guide to the total cost.

This is why comparing two mortgages on interest rate alone can mislead you. A lender offering 6.3% with heavy fees may cost more than one offering 6.5% with none. Comparing APR to APR catches that.

The caveat: APR assumes you keep the loan for its full term. If you'll move or refinance in five years, a loan with high upfront fees looks worse in reality than its APR suggests, because you never get to amortise those fees across thirty years.

On credit cards

Here's the part that confuses people: on credit cards, APR and interest rate are effectively the same number. Cards don't charge origination fees, so there's nothing extra to fold in. When a card advertises 23.99% APR, that's the interest rate.

What actually matters on a card is that this annual figure gets applied monthly. A 24% APR is charged at roughly 2% per month on your balance. On $5,000 that's about $100 in the first month alone.

Your card has several APRs

Cardholder agreements list different rates for different activity, and people are frequently caught by the ones they didn't read:

• Purchase APR — the headline rate on normal spending
• Cash advance APR — almost always higher, and typically starts accruing immediately with no grace period, plus a separate fee
• Balance transfer APR — often 0% promotionally, then reverting to a standard rate
• Penalty APR — can approach 30% and may be triggered by a payment being sufficiently late

Cash advances are the one that surprises people most. Withdrawing cash on a credit card is a fundamentally more expensive transaction than spending on it.

Variable vs fixed

Most US credit card APRs are variable, tied to the prime rate. When the Federal Reserve moves rates, your card rate generally follows within a billing cycle or two — without you doing anything. A rate you signed up for is not a rate you keep.

The grace period is the loophole

Here's the genuinely useful part: most cards charge no interest at all on purchases if you pay the statement balance in full by the due date. That's the grace period, and it means a 24% APR card can cost a disciplined user exactly nothing.

Two things to know. Carrying a balance typically forfeits the grace period — new purchases then start accruing interest immediately until you clear the balance entirely. And cash advances usually have no grace period at all, ever.

What to actually do with this

• Comparing mortgages or loans? Compare APR, and ask how long you expect to hold the loan.
• Comparing credit cards you'll pay in full? The APR barely matters — rewards and fees matter more.
• Comparing cards you might carry a balance on? The APR is the most important number on the page.
• Read the cash advance terms before you ever need them.