(Bloomberg) -- More US consumers are relying on their credit cards each month — and many are doing so without knowing the interest rates they’re paying.

Around 46% of cardholders don’t pay off credit cards in full each month, according to data collected by Bankrate LLC in December, up from 39% a year earlier. About 43% of those with debt aren’t aware of the rates associated with their cards, according to the firm.

The figures add to signs that borrowers may be in over their heads with new debt. Consumers are struggling with payments that have become more costly in recent years, as interest rates are expected to hit a four-decade high in 2023 and more car payments than ever before exceed $1,000 a month. The Federal Reserve, working to bring inflation under control, has indicated more rate increases are needed.

Total US consumer borrowing rose $28 billion in November from the month before, according to the most recent Fed figures, topping the median forecast of $25 billion in a Bloomberg survey of economists. 

“It is more expensive to buy goods and services that households need,” Michaela Pagel, a Columbia Business School professor, said in an email. “These increased costs of living might be reflected in credit-card balances and households may have trouble meeting their obligations if their wages stayed constant.”

The US government’s December jobs report showed wage growth decelerating amid inflation. Those who make more money are likelier to pay their credit-card bills in full each month, the data showed.

“People may not be fully aware of how expensive credit-card debt — or other alternative loans — are, and that interest on these loans compounds,” Pagel said. “If somebody rolls over $5,000 of credit card debt over five years, it balloons into $12,441 at 20% interest.”

Around 45% of those making less than $50,000 a year cleared their balance each month, compared with 63% of those making $100,000 or above, Bankrate said.

(Updates with Fed data in fourth paragraph.)

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