Which? has named Aldi the UK's cheapest supermarket for September 2026, based on a basket of 93 popular everyday items priced at £159.48. The result marks Aldi's eleventh consecutive month as Which?'s cheapest supermarket, continuing an unbeaten run throughout 2026 after being named Which? Cheapest Supermarket of the Year for 2025 and Best Value Brand of the Year.
Price gap widens significantly
The findings show the price gap between Aldi and its competitors continues to widen significantly. In January, rival supermarkets were an average of £30.51 more expensive. By September, that gap grew to £38.57 - meaning shoppers could have kept £333.82 in their bank accounts over the last nine months just by shopping at Aldi over an average rival supermarket.
Even when compared directly against major traditional retailers with loyalty schemes applied, the savings remain substantial, according to Which?:
- Tesco (incl. loyalty discount) was £28.23 more expensive
- Sainsbury's (incl. loyalty discount) was £29.47 more expensive
- Morrisons (incl. loyalty discount) was £33.45 more expensive
- Waitrose was £63.90 more expensive
Reaction from Aldi and Which?
Julie Ashfield, Chief Commercial Officer at Aldi UK, said: "Families shouldn't have to make sacrifices to the activities, treats, or hobbies they enjoy just because everyday household budgets are under pressure. The latest Which? data clearly demonstrates that shoppers can make substantial, ongoing savings simply by changing where they do their weekly shop.
"As the price gap between Aldi and traditional supermarkets continues to grow, that's extra cash staying directly in customer pockets for days out, family treats, or saving towards Christmas. Shoppers don't need to change their lifestyle to save money – they just need to change their supermarket."
Reena Sewraz, Which? Retail Editor, said: "With energy bills a major concern as the cold weather approaches, many households will be looking for ways to trim the cost of their food shop.
"A £60 mark-up on everyday groceries is a steep price to pay for store loyalty. 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."
Full September results
The full results for September are below, showing the average price of a basket of 93 items at each retailer:
- Aldi — £159.48
- Lidl (including loyalty discount) — £161.48
- Lidl — £161.84
- Asda — £186.71
- Tesco (including loyalty discount) — £187.71
- Sainsbury's (including loyalty discount) — £188.95
- Morrisons (including loyalty discount) — £192.93
- Morrisons — £193.13
- Tesco — £193.45
- Sainsbury's — £195.01
- Ocado — £208.64
- Waitrose — £223.38
