Nineteen million consumers will spend £3.85bn on Boxing Day sales this year, three per cent more than in 2015, a study by the Centre for Retail Research (CRR) found.
A third of those shoppers will hunt for bargains online, spending £900m, up seven per cent from the previous year, while £477m is set to be spent on smartphones and tablets.
But the high street will still wrangle in the bulk of spending, with £2.95bn anticipated to be cashed on in-store Boxing Day deals.
Much like Black Friday, Boxing Day is no longer a one-day event for retailers.
From 26 to 29 December, UK consumers are expected to spend £7.6bn, 67 per cent of which will be spent on the high street.
Big brands will produce the best results as Brits search for deals on designer goods including bags, clothes, footwear and sports leisure wear.
Electronics like laptops, TVs and smartphones will also be popular purchases, the CRR found.
Consumer appetite for deals is stronger than ever, said Claire Davenport, managing director of VoucherCodes.co.uk, who commissioned the study.
“Although the high street is still the favourite for discount shoppers, online spend is steadily increasing year on year," Davenport said.
"Retailers can capitalise on this by offering incentives such as exclusive online deals and benefits for shoppers who sign up for newsletters to draw in even more bargain hunters this Boxing Day and beyond."