Which UK supermarket is cheapest? The monthly Basket Index
Each month, Shopsplit compares a 30-item basket of everyday grocery staples at Tesco, Sainsbury’s, Asda, Morrisons, Ocado and Waitrose. Explore the results captured around month-end, see which store was cheapest for that basket, and compare potential savings from splitting across stores.
September 2026
Asda was cheapest for a third month at £90.04, its lowest total yet, and Ocado, Asda and Waitrose won again as the best three-store split. Promotions cut deeper than in August, but Tesco and Sainsbury’s ran no public offers on the basket: every discount needed a Clubcard or Nectar card.
Read the full September breakdown →Past editions
Every monthly Basket Index, in order. Prices and the cheapest split are re-checked from scratch each time; rankings can and do shift month to month.
How the Basket Index works
The short version. Every edition has its own full methodology, including exactly how products are matched and how promotions are handled.
A fixed 30-item basket
The same everyday staples (bread, milk, cheese, tea, cleaning products, fresh produce and more), priced identically every month, so editions are genuinely comparable.
Every price individually verified
No price is trusted from a feed alone. Each of the 180 store/item combinations is checked directly against the retailer before publication.
Every possible split tested
We don’t guess at a good split: we calculate the true cheapest combination of one, two, three, or more stores, and show what each option actually saves.
Common questions
Is the cheapest supermarket always the same? ▾
No, and that’s the point of running this every month. Promotions, restocks and pricing changes mean the ranking genuinely moves. A store that’s cheapest one month can drop to mid-table the next.
Why does splitting save more than just picking the cheapest store? ▾
Because no single supermarket is cheapest on everything. One store might win on dairy and lose on household goods. Splitting means buying each item from wherever it’s cheapest that month, instead of accepting one store’s full-price items to get its bargains.
Do these prices include loyalty cards like Clubcard and Nectar? ▾
Each edition lets you choose. You can view standard shelf prices, prices including publicly available promotions, or prices including loyalty-card pricing, because the cheapest supermarket genuinely changes depending on which cards you carry.
Does this include Aldi or Lidl? ▾
Not currently. Aldi’s limited online range and small number of national brands make a like-for-like 30-item basket impossible to build fairly. We’re looking at how to include discounters fairly in a future edition.
How is this different from doing it myself with the Shopsplit app? ▾
This index is a fixed, published snapshot for a standard basket, useful for tracking the market generally. The app runs the same kind of comparison on your actual shopping list, which will save you more since it’s tailored to what you actually buy.
Get your own personal price comparison
This index tracks one fixed basket for the whole country. Your household’s shop is different: the Shopsplit app checks your actual list against live prices, finds the cheapest split, and flags substitutes and promotions worth taking.
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