By employing ambiguous labelling, supermarkets are allegedly making it tough to locate the best prices.
Which? experts said that by failing to uniformly mark the price of items according to a common unit of weight, retailers are keeping shoppers in the dark.
According to its findings, various product variants at the same store may cost as much as three and a half times more (346%) per unit without disclosing this.
Which? monitored the costs of 10 common foods in the “Big Four” supermarkets, Tesco, Asda, Sainsbury’s, and Morrisons, including Coca-Cola, own-label semi-skimmed milk, Dairy Milk chocolate, Nescafe instant coffee, and Weetabix.
They discovered that Tesco offered up to 17 different Coca-Cola sizes at costs ranging from 11p to 50p for 100ml.
Purchasing four 250ml glass bottles costs £5, which is 346 percent more than purchasing a 1.5 litre bottle, which costs £1.68.
Which? also discovered that the cost of own-brand semi-skimmed milk at Morrisons ranged between 6p and 13p per 100ml, or 133% more for a consumer purchasing a 500ml bottle (65p) than a 2.27-litre bottle (£1.27).
The consumer advocate discovered that it was difficult to compare prices meaningfully for numerous fruits and vegetables, such as pears and tomatoes.
This is due to the fact that shops utilise a range of pricing descriptions, such as per pack or per kilogramme.
The price per unit was often plainly posted but did not apply to a special deal, promotion, or other price decrease.
According to Which?, there are several instances of pricing that is difficult to understand or is completely absent.
This applied to purchases made at stores like Tesco for a pack of tomatoes, Waitrose for Penguin bars, Morrisons for some soft fruit, and M&S for vine tomatoes.
‘At a time when food costs are a big issue, unit pricing may be a valuable tool for customers to compare and pick the cheapest products, but imprecise supermarket pricing means the great majority of people are left unable to find the best bargain,’ said Sue Davies, director of food policy at Which?
Small savings may mount up and have a significant impact, but until supermarkets make unit pricing more noticeable, readable, and consistent — in addition to include it on their promotional offers — shoppers will continue to run the risk of not receiving the best deal.