WASHINGTON — Americans are feeling confident enough in the economy to go back to a time-honored tradition – taking on a little extra debt.

Consumer borrowing surged in November by $20.4 billion, the Federal Reserve said Monday. It was the third straight increase and the largest monthly gain in a decade.

The jump in borrowing was largely because people took out more loans to buy cars and swiped their credit cards frequently to purchase holiday gifts.

In November, total consumer borrowing rose to a seasonally adjusted $2.48 trillion. That’s just below the $2.52 trillion that consumers borrowed in December 2007, the month that the country fell into recession.

Total borrowing is up from a post-recession low of $2.39 billion in September 2010. Borrowing tumbled to that level after consumers slashed their debt for nearly two years.

Consumers have increased their borrowing in six of the past nine months. Americans are taking on more debt after seeing the unemployment rate drop and the economy improve, albeit modestly.

Many are also leaning on their credit cards and loans to make up for wages that haven’t kept pace with inflation this year.

In the Fed’s report, the category that measures credit card debt rose in November by $5.6 billion, the most since March 2008. Its gauge that tracks auto loans increased $14.8 billion, nearly matching July’s gain, which was the biggest since February 2005.

Sung Won Sohn, an economics professor at the Martin Smith School of Business at California State University, said many consumers were likely persuaded by incentives that retailers and auto dealers offered to boost sales.

Still, Paul Edelstein, director of financial economics at IHS Global Insight, expressed concern that consumers may have relied on their credit cards to finance holiday purchases.

The rise in borrowing comes as many consumers are seeing little to no growth in their paychecks. Inflation-adjusted, after-tax incomes shrank by nearly 2 percent in the July-September period.

To make up the difference, many consumers have reduced the amount they save. The savings rate fell in November to 3.5 percent, the lowest level since the recession began. In 2008, the savings rate jumped to 5 percent and stayed above that level until early last year.