Which? has named Aldi the UK's cheapest supermarket for its monthly grocery basket analysis, with the discounter beating rival Lidl and major chains Tesco and Sainsbury's—even when loyalty card prices are considered. According to the consumer group, shoppers buying the same 93 items would pay £159.48 at Aldi, while the identical shop at Waitrose would cost £223.38, a difference of £63.90.
The findings come from Which?'s September price comparison, which tracks the cost of up to 200 branded and own-label products daily across eight major supermarkets. The data is supplied by an independent price comparison company, and for stores without online prices, Which? says it sends fieldworkers to collect prices in person.
Lidl close behind, Asda beats Tesco and Sainsbury's
Lidl finished second in the analysis, with the same basket costing £161.48 for shoppers using a Lidl Plus loyalty card, or £161.84 for those without the card. Asda came third at £186.71, ahead of Tesco at £187.71 and Sainsbury's at £188.95.
Waitrose was again the most expensive supermarket in the monthly analysis, with the basket costing £223.38, while the average Ocado shop came to £208.64. The price gap between Aldi and Waitrose means a shopper switching from the premium chain could save more than £60 on a single grocery run.
Loyalty discounts and the cost of store loyalty
Which? recorded 46 loyalty discounts across the supermarkets in September: 22 at Tesco, 21 at Sainsbury's, two at Lidl, and one at Morrisons. Despite these offers, the discounters still came out on top, with Aldi and Lidl undercutting the traditional big four by a significant margin.
Reena Sewraz, Which?'s retail editor, said: “A £60 mark-up on everyday groceries is a steep price to pay for store loyalty.” She added: “September's analysis proves once again that the discounters are the place to go to save – and when the cost gap is that wide, switching where you shop remains the quickest way to cut your grocery bill.”
How Which? conducts its monthly price check
Each month, Which? compares thousands of prices at eight of the UK's major supermarkets: Aldi, Asda, Lidl, Morrisons, Ocado, Sainsbury's, Tesco, and Waitrose. The analysis tracks up to 200 branded and own-label products daily over a month to calculate the average cost per item.
The latest results reinforce the price advantage of discount retailers, with Aldi maintaining its position as the cheapest option for the second consecutive month. For shoppers looking to reduce their grocery spending, the data suggests that switching to a discounter remains the most effective way to cut costs, with potential savings of over £60 per basket compared to the most expensive options.
