The Olympics and Paralympics are set to inject a £804m shot in the arm to the economy during the seven week period.
Research by Visa Europe shows the Games are to create an economic legacy worth £5.33bn by 2015.
High street retailers are set to enjoy a £210m uplift while the grocers are forecast to increase their income by £88m.
The payment technology company studied consumer spending at previous games and major sporting events to forecast an £803.6m increase in consumer spending – £54.3m from domestic consumers and £749.3m from those visiting the UK.
Visa predicts the games will create a £3.54bn impact in long term visitors spending and the total stimulus to the economy will be £5.33bn, made up largely of £4.12bn between 2013 and 2015.
Visa Europe commercial director Steve Perry said: “While the host city will be the centre of Olympic activity and the initial spending beneficiary.
“The Games are a showcase for the whole country. Visitor spending and associated economic output will rise on the back of the nation’s high profile as a desirable destination in coming years.”
Established tourist destinations including the South West of England and Scotland are also forecast to see an uplift in spending following the games.
However, retailers at Westfield Stratford City are upset after being told this week that they will have to shut early on the day of the Olympics ceremony.
Businesses on the site will have to close at 3pm on July 27. “The centre will be required to close at 3pm to assist LOCOG with the logistics of the Opening Ceremony,” Westfield said in a statement.
The centre’s restaurants cafes and cinema will remain open for customers with bookings.
“The required change to Opening Ceremony Day centre trading hours is a consequence of the centre being located at the Gateway to the Olympic Games. Whilst this is largely out of our control, we expect the Games to be a wonderful showcasing opportunity for the retailers in the centre,” Westfield said.
Westfield Stratford City is expected to have a 30% increase in trading hours during the Games.