When people feel like shopping, they are increasingly pulling out iPads and other tablets, so much so that shopping on tablets could someday outpace shopping on smartphones and even computers.

That is the conclusion of a report by Forrester Research that is to be published Monday, based on a joint survey with Bizrate Insights. Even though just 9 percent of shoppers own tablets, sales from tablets already account for 20 percent of mobile e-commerce sales, the report said, and 60 percent of tablet owners have used them to shop.

“Everyone thinks that mobile phones and mobile commerce are the next big things, and I think what this data shows is it’s probably actually tablets,” said Sucharita Mulpuru, an e-commerce analyst at Forrester who co-wrote the report. “We have always capped e-commerce at 10 to 15 percent of total retail sales, but this potentially has the capability of really expanding e-commerce much beyond that.”

Tablets offer retailers and shoppers something that cellphones and computers cannot — the experience of flipping through a print catalog, with big photos and rich imagery — and with shorter load times than many Web sites.

For instance, TheFind’s Catalogue for the iPad, which includes retailers like Crate & Barrel and Sephora, lets people flip through pages. Gilt’s Jetsetter app for travel uses the iPad’s accelerometer and gyroscope to show resorts from different angles. Retailers can send personalized catalogs to customers’ tablets based on their interests and purchase history, Ms. Mulpuru said.

For retailers, these types of features give them a chance to show off their products instead of competing solely on price with dozens of other retailers accessible with a Google search and a click. For shoppers, 80 percent of whom use their tablets in the living room, they make online shopping a leisurely experience in a way it hasn’t been since e-commerce came along.

“The element of discovery is missing online, because most people go to Google, and Google isn’t about discovering something online, it’s about typing something into a search box,” Ms. Mulpuru said. “This is much closer to the actual physical browsing experience.”

Forty percent of tablet owners use their tablets instead of their personal computers when both are available, Forrester found. And though more people are shopping on smartphones, they use them mostly for comparing prices and receiving mobile coupons, and get frustrated by the small screen when browsing items or entering billing information. A majority, particularly young people, prefer shopping on tablets, the report said.

Still, retailers have been slow to catch on. The average retailer has spent just $14,000 developing shopping tools for tablets, which Forrester calls “anemic.” And though Forrester expects that a third of adults will own tablets by 2015, the majority of people will not own the devices.