The sums are pricey — in some cases more than $7.5 million — but running one-minute commercials seems to be the norm for the big NFL game on Feb. 3.

Longer commercials are part of a plan to win the attention and the affection of viewers — tens of millions of people watch the Super Bowl each year, and many can’t wait for the breaks in action to see the ads. A Harris Interactive study last year found that an estimated 66 percent of women and 45 percent of men watch as much for the commercials as for the action on the field.

CBS executives say demand has been heavy for this year’s game, which will be between the Baltimore Ravens and the San Francisco 49ers. The majority of ads likely will still be 30-second spots, which have sold for a record-high average of $3.8 million — 7 percent higher than last year’s rate.

A few spots have gone for as much as $4 million, which should help CBS rake in more than $275 million in advertising revenue from the game alone, on top of the millions of additional ad dollars generated during seven hours of pregame shows.

Demand, advertisers say, is driven by interest. More than 41 million viewers watched the Ravens beat the New England Patriots on Sunday in the AFC championship game, and the Super Bowl is expected to draw more than 100 million viewers. Last year’s audience in the U.S. of 111 million people was more than twice the size of any other single event televised in 2012.

“I’ve been doing this for 30 years and consumer interest is at an all-time high,” said Mike Sheldon, chief executive of ad agency Deutsch LA, which is creating Super Bowl commercials for Volkswagen and Taco Bell.

“The Super Bowl is a cultural phenomenon — it’s a social event that people want to be part of,” said Carisa Bianchi, president of Los Angeles’ largest ad agency, TBWA\Chiat\Day, which is creating a spot for Pepsi Next.

Last year, the number of 60- and 90-second messages in the Super Bowl surged. Nearly 20 percent of the ads stretched 60 seconds or longer, according to ad tracking firm Kantar Media. (Only 10 percent of the ads in 2011 were a minute or longer.)

Last year’s most discussed spot, Chrysler’s two-minute “It’s Halftime in America” with Clint Eastwood, might have encouraged more marketers to think longer this year.

“At the Super Bowl, everyone wants to be blown away,” said Chris Adams, executive creative director of Saatchi & Saatchi LA, which is designing a 60-second ad for Toyota. “One way to do that is by going bigger and longer to have more fun with the storytelling.”

Marketing executives must employ new tactics as the price of the time escalates and as the TV networks cram more spots into the game, said Jon Swallen, Kantar Media’s senior vice president of research.

Last year’s broadcast included more than 47 minutes of commercials, compared with 40 minutes in 2005.

Swallen estimated that this year’s game will feature 60 commercial messages, from 30 to 40 advertisers. “That’s a lot of competition,” Swallen said. “The driving force is this desire to break through the clutter and tell a story.”

Advertisers continue to be torn over whether the big game is worth the cost. This year, General Motors and Honda put themselves on the sidelines. There won’t be a shortage of cars, however, with nine automakers represented, including Audi, Chrysler, Fiat, Kia, Toyota and VW.

During the past decade, advertisers have spent $1.85 billion on commercial time in the Super Bowl, Kantar Media found.