Almost half (46%) of UK smartphone owners have used their device to research product information before or during a shopping trip, according to a survey of more than 2,000 consumers by Deloitte Digital.

These numbers tally with a survey of European consumers by Tradedoubler which found that 42% of smartphone owners use their device to compare prices in-store, while 13% claim to have switched stores after finding a better offer elsewhere.

As a result, Deloitte estimates that around 6% of in-store retail sales will be influenced by smartphone use, equivalent to £15.2bn of sales per year.

This is almost double the value of direct purchases made through mobile, which Deloitte puts at £8bn in 2012.

However this might actually be a conservative estimate, as data included in our UK Mobile Statistics Compendium shows that 17% of UK mobile web users say mobile has influenced their in-store purchase. 

Therefore, based on Deloitte’s estimates, mobile may actually be influencing in-store purchases worth up to £45bn per year.

The use of smartphones also appears to increase conversion rates in-store for retailers. According to Deloitte almost three-quarters (74%) of UK shoppers that visited a retailer’s mobile website or app during their most recent shopping trip made a purchase.

This highlights the importance of offering consumers a way to engage with your brand through mobile and also emphasises the need for retailers to install free Wi-Fi in-store so shoppers can easily access the information they need to encourage a purchase.

The impact of mobile on in-store purchases varies depending on the sector. In electronics it influences 10% of sales compared to just 2.9% for convenience stores and 3.8% for supermarkets.

But while 64% of smartphone owners have used their device to make a bank payment or pay a bill, just 1% have used their phone to make an in-store payment.

A similar Deloitte study in the US found that mobile influenced around 5% of sales, which equates to around $159bn of in-store sales.