ATLANTA — If you used a “buy now, pay later” option during the holidays, consumer experts say now is the time to pay up.

Data show a nearly 10 percent increase in the number of people using “pay in four” or buy now, pay later plans. WSB consumer expert Clark Howard says the numbers also show that about one in three of those purchases will not be paid off on time.

“People are going to mess up their credit, and they may have all kinds of junk fees they now have to pay,” Howard said.

Howard says the plans can sound appealing, offering four easy installments with no interest, but the reality is many consumers fall behind.

“The reality is, and the data shows, that about one out of three of these aren’t going to get paid in time,” he said.

Howard warns missed payments can hurt credit scores and trigger added fees. He urges shoppers to pay off balances as soon as possible and avoid future purchases they cannot afford upfront.

“If you think the bank is trying to do something nice for you, the next thing you know you get sucker punched,” Howard said. “If you don’t have the money, don’t buy it.”

WSB Radio’s Sabrina Cupit contributed to this story.