About 4.3m people are likely to splash out an average of 27.90 each and Boxing Day is expected to be the busiest day of the year for etailers.
Last year consumers spend 102m online on Christmas Day as retailers such as Marks & Spencer and John Lewis, along with pureplays such as Play.com and M&M Direct, launched their Sales.
Last year s online shopping trends are expected to be replicated, industry body IMRG said, bringing anticipated online sales growth in December of 14%, totalling about 5.2bn.
Experian Hitwise research director Robin Goad said: Over the last few years the importance of these two days has been increasing and we see not reason for it to be different this Christmas.
We have already seen that shoppers are willing to hold out for longer for a bargain this year, with cyber Monday moving a week closer to Christmas.
This behaviour is likely to carry through to the post-Christmas period, with people logging on after Christmas lunch to find the best discounts before hitting the high street and shopping malls the following day.
