NEW YORK: Four in ten US smartphone owners will use that device to redeem a coupon during 2014 according to digital intelligence business eMarketer.

It estimated that a total of 59.2m US adult smartphone users would do so over the course of the year, representing a 37.5% increase on 2013, and said these mobile coupons were being used for both online and offline shopping.

Separately, Forrester Consulting recently carried out in-depth surveys with 500 digital coupon users for RetailMeNot.com, the digital coupon site, and found that most redeemed a digital coupon code within three days of receiving it, and nearly one-third redeemed it immediately.

The most common method of redeeming digital coupons was by purchasing something on a computer (33%), but over one quarter (27%) made a trip to a store for this purpose. Some 25% used a smartphone and 14% a tablet.

The primary source of coupons was passive receipt via an email from retailers, cited by 57% of respondents, but this was only just ahead of the 55% who actively sought them out using search engines on their smartphones. And around one third relied on coupon-related apps or emails from a coupon company.

Forrester also said that younger shoppers were leading the way, with fully 60% of consumers under 35 ultimately redeeming a coupon on their phone. "This points to a new emerging future of shopping, with mobile at the center of the experience," said the report.

Customers were also found to be inclined to spend more than anticipated in-store when using coupons, making customer service an important part of the overall process.

"Easy redemption, mobile-formatted coupons, and a balanced marketing plan will drive users to the store and online properties which, in turn, provides opportunities for conversion and increased spend by consumers," the report concluded.

Data sourced from eMarketer, Forrester Consulting; additional content by Warc staff