APR stands for Annual Percentage Rate — the yearly cost of borrowing money, written as a percentage. It's the number lenders are legally required to show so you can compare loans and credit cards on something close to a level playing field. Understanding it is the difference between knowing what a debt actually costs and just hoping it's fine.
APR vs. interest rate: what's the difference?
People use the terms interchangeably, but they aren't the same. The interest rate is the cost of borrowing the principal alone. The APR bundles the interest rate plus certain required fees (like some origination charges) into one yearly figure. That makes APR the more honest comparison number: two loans can share an interest rate but have very different APRs once fees are included.
How APR is applied day to day
Lenders don't charge you once a year. They convert the APR into a smaller rate for the billing period — for a credit card, the daily periodic rate is the APR divided by 365. That daily rate is applied to your balance, which is why carrying debt gets expensive faster than the headline number suggests.
APR ignores compounding within the year; APY (annual percentage yield) includes it. For a savings account you want a high APY. For a debt you want a low APR — and because of compounding, the real cost of that debt can edge slightly above its stated APR.
Fixed vs. variable APR
A fixed APR stays the same (though it can still change with notice). A variable APR moves with a benchmark rate, so your cost rises and falls with the wider market. Most credit cards are variable, which means "today's APR" isn't a promise about next year.
Not all APRs on a card are equal
- Purchase APR — the rate on everyday spending.
- Cash-advance APR — usually much higher, often with no grace period (interest starts immediately).
- Penalty APR — a punitive rate triggered by missed payments.
- Promotional / intro APR — a temporary low (sometimes 0%) rate that expires on a set date.
How to use APR when comparing offers
- Compare like with like — same loan type and term.
- Check what's included — some fees aren't captured in APR.
- Watch expiry dates on promo rates and what the rate reverts to.
- Fixed or variable? A low variable APR can climb.
The bottom line
APR is the yearly price tag on borrowed money, fees included. It's the fairest single number for comparing debt — but only if you compare the same product, read the fine print on fees and promos, and remember that compounding can quietly push your real cost a little higher.
General education, not financial advice.
Sources & further reading
Related
- 📖 How credit card interest works
- 📖 Compound interest explained
- ▶ Play Maxed Out — feel APR in fast-forward.
- 📚 More explainers in the Learn hub