Allsupers Pricemonitor — edition 2026-08

How to read this index - We compare branded groceries across nine of the twelve categories in the ONS price basket. Fresh fruit, vegetables and fish are left out. UK supermarkets sell these mostly under their own labels, and the branded items they do sell are rarely stocked by more than one chain. After matching, only two fruit products, eighteen vegetable products and twenty-seven fish products could be compared across shops. That is too few to measure a category. - Those three categories are 22% of the ONS basket, and the weights of the remaining nine are scaled up to fill the gap, which lifts bread and cereals from 18.0% to 23.1% of this index. These figures compare branded packaged goods, not the cost of a full shopping trip. - Aldi's level rests on 26 comparable products in total. In meat, which carries 22.4% of this index, it rests on one. - Iceland and Asda are too close to call. Their confidence margins overlap, so read them as a leading pair rather than as first and second place. - Where a shop was running a cheaper offer on a product, we use the offer price, including multi-buy offers, where the price only applies if you buy more than one. These are not spread evenly: about a third of Iceland's compared products were on such an offer, while Aldi, Waitrose and the Co-op had none. Priced without multi-buy offers, Iceland would fall from the top to fifth of the eight ranked shops, and Asda would come first. We are settling this rule for the September edition. - One consequence is worth saying plainly: some of these per-unit prices come from offers you only get by buying more than one, so the figure is the price per unit of the cheapest way to buy the product that day, not the price of buying a single one. - Morrisons, Ocado, Waitrose and Co-op are each clearly apart from their neighbours, so the order between them can be read as a ranking. Morrisons is the narrowest of those: it is about 3 index points above Sainsbury's, and our test separates the two on every one of the twenty seeds we tried, but only just: the lower end of the test's range clears equality by between 0.4 and 0.9 points. Read it as a reliable separation and a small one, and see the note on meat below. Tesco and Sainsbury's are also too close to call. We tested each of the seven neighbouring comparisons directly, on the index itself and allowing for products that share a brand. That is a stricter test than the confidence margins shown here and a sharper one than whether two bars in the chart overlap, so a pair can be clearly apart even where their bars appear to touch - and these verdicts cannot be reproduced from the intervals in the table. - Meat carries 22.4% of this index but rests on 198 branded products, mostly sausages and bacon; 11 of them are meat-free sausages filed under meat. It decides the closest calls: without meat, Iceland would be clearly cheaper than Asda, Tesco clearly cheaper than Sainsbury's, and Morrisons only borderline apart from Sainsbury's. The order of the shops would not change. - Prices are as of 31 August, or the most recent earlier date on which we surveyed each shop; the product list is as of the build date, so items withdrawn in between are not included.

August 2026 (own-label basket): - We changed how this basket is built. A comparison now counts only when our matching check judges the two products similar, and for each shop we take the most similar product our check has confirmed rather than the cheapest of several similar ones, because picking the cheapest makes a shop with a broad range look cheaper. Products sold by the piece are now included, compared only with products of a similar piece count. The basket therefore compares standard own-label lines; premium ranges rarely pass the check. These are changes of method, not of prices: all prices are as of 31 August. - Aldi is ranked here and not in the branded table above. That is the same coverage rule applied twice, not an inconsistency: own label is most of Aldi's range, and national brands are not. Aldi has no own-label personal care product similar enough to compare, so that category is left out of Aldi's figure. - Aldi is the cheapest and Tesco the second cheapest of the ranked shops in every resampling of the basket we ran, and the Co-op and Waitrose are clearly the two most expensive. Morrisons and Ocado are too close to put in order. - Asda is shown but not ranked. Our own system failed to collect Asda's fruit and vegetables from 11 May to 6 October 2026, so those two categories are missing for Asda; the fault is ours, not Asda's. On the categories we do have, Asda sits between Tesco and Sainsbury's, whether or not fruit and vegetables are counted for the other shops. We do not say whether Tesco or Asda is cheaper. - Iceland is shown but not ranked: its own-label range has no products similar enough to compare in fish, in personal care, or in sugar and sweets. - One shop needs a caveat. About a quarter of the Co-op's products in this basket were on offer, against fewer than one in thirteen across its whole range. Almost all of those offers are the Co-op's Aldi Price Match prices, which this basket picks up because it compares products with Aldi's. Leaving out the products on offer would put the Co-op at about 156 instead of 143.9; it would still be the second most expensive. - Waitrose needs a caveat too. Most of Waitrose's own-label meat is free range, slower reared or organic, which our matching check treats as a different product from standard meat, so only 8 Waitrose meat products count in this basket, against 57 to 169 at the other ranked shops. Meat carries about a sixth of the basket's weight. Leaving Waitrose's meat out would put Waitrose at about 157 instead of 161.3; it would still be the most expensive. - Three categories hold fewer products than we aim for: fish, soft drinks and personal care. Leaving them out entirely moves no shop by more than two points. - The uncertainty range next to each shop allows for products that are matched to the same shop product more than once: one Co-op milk, for example, is the Co-op match for twelve milks in this basket. We treat such products as one group when we work out the range, so a shared price never counts as extra evidence. This makes the ranges wider than our earlier method gave; our earlier editions did not allow for this, so their ranges were too narrow. It changes no rank. - Where one shop's organic own-label product would be compared with another shop's conventional one, we remove the comparison: organic is priced as a different product. Comparisons between two organic products stay. - Where a shop's product comes in a pack more than twice or less than half the size, or costs more than three times as much or less than a third as much per kilo, litre or item, a second check looks at both products again, including their pack photos. When it is in doubt we use the shop's next most similar product, or leave that shop out for the product: 38 comparisons were replaced or left out this way. - Every comparison in this basket was judged by our matching check. We have not yet read a random sample of this month's comparisons by hand to measure how often that check is wrong.