There’s no single, permanent answer to which supermarket is cheapest, because a supermarket price comparison only means anything if you know exactly how the basket behind it was built. As of June 2026, Which? found Aldi cheapest for a mixed 95-item basket at £163.34 on average, while a separate, larger branded-goods list put Tesco with Clubcard on top instead. Both are correct, they’re just answering different questions.
That’s the real problem with most “cheapest supermarket” articles: they publish a number and let it go stale. This one instead explains how the comparisons are actually built, why two reputable trackers can disagree, where loyalty pricing distorts what you see on the shelf, and gives you a method to run the comparison yourself with your own weekly list, since that’s the only version of this answer that stays useful past this month.
Which Supermarket Is Cheapest for a Weekly Shop? It Depends on the Method
Ask this question and you’ll get a different answer depending on three things: which items are in the basket, whether loyalty prices are included, and how many supermarkets are being compared. A basket built entirely from own-label staples favours Aldi and Lidl, since their limited ranges are optimised for exactly those categories. A basket with specific branded items, say Heinz, Kellogg’s or Hovis, can’t be priced at Aldi or Lidl at all, since they don’t stock the full branded range, so any comparison including those products has to use a different set of supermarkets entirely.
This is why serious supermarket price comparison work, like the ongoing tracker run by Which?, actually publishes two separate lists rather than one: a smaller list every retailer can fill, and a longer branded list restricted to the full-range supermarkets. Treat any single “cheapest supermarket” headline with a bit of caution unless it tells you which type of basket it’s using.
How Basket Comparisons Are Actually Built
The credible trackers all work roughly the same way, even if the details differ. Which? compares prices across eight major UK supermarkets, Aldi, Asda, Lidl, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose, tracking a fixed list of items monthly and publishing the average total cost per store, according to Which?’s own published methodology.
The mechanics matter here. A comparison is only meaningful if:
- The same brand and pack size is used at every store where it’s available, not just “a similar product”
- Own-label substitutes are used consistently where a branded item isn’t stocked, rather than swapping in whatever happens to be cheapest that week
- The list is refreshed regularly enough to catch price changes, but fixed enough that month-to-month comparisons are actually comparing the same thing
- Both standard and loyalty-scheme prices are recorded separately, since these can differ by more than 10% on the same product
Miss any of these and the comparison quietly stops being a fair one, even if the final number looks precise.
Why Which? and Trolley Reach Different Answers
This trips a lot of readers up, since both are legitimate, well-regarded tools that answer genuinely different questions. Which? publishes a monthly snapshot: a fixed basket, priced across eight supermarkets, with one total figure per store. It’s built to answer “which supermarket was cheapest overall last month,” and it does that well, but it can’t tell you anything about a specific product you personally buy that isn’t on its list.
Trolley.co.uk works the opposite way. It’s a live product-level database covering a wider range of retailers, including Aldi, Asda, Tesco, Ocado, Morrisons, Waitrose, Co-op, Sainsbury’s and others, letting you search an individual item and see where it’s currently cheapest. That makes it far better for checking one specific product before you buy it, but it isn’t designed to hand you a single “cheapest supermarket” verdict for a whole trolley the way Which?’s monthly comparison does.
So the two tools aren’t in competition, they’re solving different problems. Which? tells you the overall pattern across a representative basket; Trolley tells you the current price of one thing you’re about to buy. Neither replaces a full personal basket comparison, which brings us to the method further down.
Cheapest Supermarket UK: What the Latest Data Actually Shows
As of Which?’s most recent comparison, dated June 2026, Aldi was the cheapest supermarket overall for the standard mixed grocery list, averaging £163.34 across 95 items, with Lidl close behind at £164.79 including Lidl Plus discounts. Asda came in third at £181.06, and Waitrose was the most expensive at £217.03 on average for the same list, according to Which?’s published figures.
On the separate, longer branded-goods list of 225 items, the picture flips: Tesco with Clubcard came out cheapest, at £580.35 with the loyalty discount applied against £629.25 without it, while Asda’s average sat close behind at £584.32. This is exactly the kind of detail that makes a single “cheapest supermarket” headline misleading on its own, since the answer genuinely depends on whether your shop leans toward own-label basics or specific branded products.
These figures will already be dated by the time you’re reading this, since Which? refreshes its comparison monthly and prices move constantly. Treat any specific number in this piece, or anywhere else, as a snapshot rather than a fixed fact, and check the current Which? comparison directly if the exact figure matters to you.
Where Loyalty Pricing Distorts the Picture
This is the biggest change to supermarket price comparison in the last few years, and it’s the single thing most stale “cheapest supermarket” articles fail to account for properly. Tesco Clubcard, Sainsbury’s Nectar, and Lidl Plus now gate a meaningful share of headline promotions behind app-based membership, meaning the shelf price a non-member sees can be substantially higher than what a loyalty member actually pays.
Which?’s February comparison found Sainsbury’s offering 14 loyalty-only discounts and Tesco offering 13 within its tracked list alone, and its longer branded comparison shows Tesco’s total dropping from £629.25 without Clubcard to £580.35 with it, a gap of roughly £49 on one shop. That’s not a rounding error, it’s the difference between two entirely different rankings depending on whether the shopper is signed up.
Practically, this means any comparison that doesn’t separate member and non-member pricing is only giving you half the picture. If you’re not enrolled in a supermarket’s loyalty scheme, the “cheapest supermarket” answer built on member pricing simply doesn’t apply to your actual shop, and it’s worth checking both figures before assuming a headline ranking reflects what you’ll really pay.
Unit Pricing Rules: What Changed After the 2023 Review
Unit pricing, the price per kilogram, litre or item shown alongside the shelf price, exists specifically so shoppers can compare value across different pack sizes without doing the maths themselves. The Competition and Markets Authority reviewed how consistently retailers were actually displaying it, publishing its findings in July 2023, and found that unit prices were often shown inconsistently between retailers, sometimes per 100 grams, sometimes per kilogram, for genuinely comparable products, which made cross-store comparison harder than it should be.
That review led to real regulatory change, and it’s happened in stages. The Price Marking (Amendment) Order 2024 came into effect on 1 October 2025, standardising the units retailers must use, kilograms, litres, square metres, cubic metres, or a simple count, so comparable products are shown using the same measure consistently. A further amendment, the Price Marking (Amendment) Order 2025, takes effect from 6 April 2026, clarifying the legal definitions of “selling price” and “unit price” and introducing a specific treatment for deposits, according to government guidance published on GOV.UK.
Practically, this means unit pricing across UK supermarkets should be genuinely more comparable from April 2026 onward than it was even a year earlier, since the same measurement basis now has to be used across similar products rather than left to each retailer’s own preference. If you’re comparing products by unit price, this is a meaningfully better tool to lean on now than it was before these changes took effect.
A Repeatable Method for Comparing Your Own Basket
None of the published trackers will ever match your actual weekly shop exactly, so here’s a method you can run yourself in about fifteen minutes:
- Write out your actual regular shopping list, using the specific brand and pack size you buy, not a generic category
- Split the list into items available at discount-range stores like Aldi and Lidl, and items that require a full-range supermarket
- Price the full list at two or three full-range supermarkets you’re realistically willing to shop at, checking both standard and any loyalty-scheme price
- Price the discount-range-compatible portion separately at Aldi or Lidl, since these often beat even loyalty prices on own-label staples
- Add both totals together for a genuine like-for-like comparison, rather than assuming one store wins across every category
- Repeat this roughly every couple of months, since promotions, loyalty terms and even product availability shift often enough to change the answer
This takes longer than reading a headline ranking, but it’s the only version of “which supermarket is cheapest” that actually reflects what you buy, rather than what a fixed national basket happens to contain.
Supermarket Price Comparison Tools: What Each One Is Actually Good For
- Which?: best for the overall monthly picture across major supermarkets, using a fixed representative basket, both with and without loyalty pricing
- Trolley.co.uk: best for checking a single specific product’s current price across a wide range of retailers before you buy it
- Your own method above: the only option that reflects your actual shopping list rather than a representative one built for a general audience
No single free tool currently replicates the old MySupermarket-style full personal basket comparison across every major supermarket automatically, so treat the tools above as complementary rather than expecting one app to do all the work end to end.
FAQs
Which supermarket is cheapest for a weekly shop in the UK?
It depends on your basket. For a mixed list of mostly own-label items, Aldi has consistently ranked cheapest in Which? ‘s monthly comparisons through 2026, while for a longer list including specific branded products, Tesco with Clubcard has recently come out on top instead.
What is the cheapest supermarket in the UK right now?
As of Which?’s most recent published comparison in June 2026, Aldi was cheapest overall for a standard mixed grocery basket, averaging £163.34, with Lidl close behind. Check Which? ‘s current monthly comparison directly for the latest figure, since this changes regularly.
Is Aldi or Lidl cheaper?
They’re consistently close, often within a couple of pounds on a full basket. Which? ‘s June 2026 data put Aldi about £1.45 cheaper than Lidl including Lidl Plus discounts, a small enough gap that location and convenience may matter more than the price difference itself.
Do I need a loyalty card to get the cheapest supermarket prices?
Increasingly, yes, for the full-range supermarkets. Tesco Clubcard and Sainsbury’s Nectar now gate a significant number of promotional prices behind membership, so a non-member can end up paying noticeably more for the same trolley than the headline “cheapest supermarket” figure suggests.
What’s the difference between Which? and Trolley.co.uk for price comparison?
Which? publishes a fixed monthly basket comparison across major supermarkets to answer which store is cheapest overall, while Trolley.co.uk is a live product-by-product database better suited to checking where one specific item is currently cheapest. They’re complementary tools rather than direct alternatives.
Did unit pricing rules change in the UK?
Yes. Following a Competition and Markets Authority review published in July 2023, the Price Marking Order 2004 was amended in two stages, with standardised units of measurement taking effect from 1 October 2025, and clearer definitions of selling and unit price following from 6 April 2026.
How often should I compare supermarket prices myself?
Roughly every couple of months is enough to catch meaningful shifts in loyalty pricing, promotions and product availability, without spending excessive time on it. Prices move constantly, so any comparison, including this article’s figures, should be treated as a snapshot rather than fixed.
