Q. I’ve paid off my balance. Why do I still see finance charges on my statement?

A. Some banks charge “trailing interest,” which accrues from the time your statement period ends until your payment is received. To avoid paying it, you need to clear your balance within 20 to 30 days (the standard grace period) of posting the charge. Yes, that means paying off the bill before you get it. (Ask your bank for a payoff amount and date.)

Another bank trick to watch out for: double-cycle billing. Here, a bank charges interest over two cycles (say, 60 days, not 30) instead of one. So even if you’ve paid off most of a bill, interest is calculated on the original, full amount for a longer span.

Q. My statement lists an APR and a daily rate. What’s the difference?

A. The APR is the annual percentage rate — the interest rate you’ll pay for the year if you carry over a balance. “All other period rates are based on the APR,” explains Scott Bilker, creator of DebtSmart.com, a website that helps consumers manage credit-card debt. “The daily rate is the APR divided by 365. The monthly rate is the APR divided by 12.” So by showing the daily and annual percentage rates, the bank is just doing the math for you.