And almost half use their phones to compare prices.
New data from digital researcher Econsultancy finds that 25 per cent of shoppers have used their phone to buy a product or service in the past year, rising from 13 per cent in 2011.
43 per cent are also using the devices for prices comparisons and reviews to make sure they're getting the best bargain available, up from 19 per cent in 2011.
Reserve and collect options are also popular for 80 per cent of people, who do so via the web and mobile apps.
Interestingly, two-thirds of respondents said they prefer to use a mobile site ahead of an app, despite the latter platform supposedly providing users with a richer experience, while around a third use smartphones to locate stores.
Ashley Friedlein, CEO of Econsultancy, said: "Consumer shopping habits andpreferences are rapidly evolving. Retailers must quickly adapt to support therise of the multichannel shopper."