Aldi crowned the UK's cheapest supermarket in August

Aldi retained its title as the UK's cheapest supermarket in August, according to Which? analayis, once again pipping Lidl to the post.

Aldi was the cheapest supermarket for a list of 92 everyday groceries – the eighth month in a row it has taken the top spot – with the shop costing £159.36 on average.

Lidl was close behind in second place, while Asda came third, followed by Sainsbury’s. Sainsbury’s also gained the upper hand in the ongoing loyalty price battle with Tesco: we found that shopping with a Nectar card was once again cheaper for our tracked basket than shopping at Tesco with a Clubcard.

Read on to find out how other supermarkets, including Lidl and Asda, compare – and how much you could save by switching supermarkets.

Cheapest supermarket in August

We checked the prices of 92 popular branded and own-brand groceries, including milk, cheese and Hovis sliced bread, at eight of the UK's biggest supermarkets throughout August to see how they compared.

The table shows how much our shopping cost on average:

Aldi came out the cheapest this month, with an overall shop costing £159.36. Lidl was pipped to the post by £1.74, with an average price of £161.10 across August. 

Asda took third place, with a shop costing £185.21 on average. 

Tesco and Sainsbury's have been locked in a tight loyalty price battle in recent months, but Sainsbury’s took the lead again this time. A basket with a Nectar card averaged £185.55, while Tesco’s Clubcard shop was £3.90 more expensive at £189.45.

Shopping without a Clubcard at Tesco would set you back £192.97 on average. 

A Morrisons shop in August sat at £194.11, and a shop at Sainsbury's without a Nectar card cost £195.33 – almost £10 more than shopping with a Nectar card. 

Waitrose was again the most expensive supermarket in our monthly analysis, with the items on our list costing £223.75, while the average Ocado shop cost £207.62. 

There were 45 loyalty discounts overall in August – 26 at Sainsbury's and 19 at Tesco.

• Find out more: cheapest supermarkets of 2026

How much of a discount do loyalty cards give?

Having a loyalty card would save an average of 1.83% at Tesco in August – but a larger 5.01% at Sainsbury's. 

This month Morrisons announced its new 'Unbeatable Prices' promise. The supermarket pledged to match or beat prices at Aldi, Asda, Lidl, Sainsbury's and Tesco across 500 core grocery lines including fruit and vegetables, bakery goods, cupboard staples and its Market Street counters. 

This replaces its previous 'Price Match' scheme, which saw it match prices with Aldi and Lidl across 200 core grocery lines. 

Back in May, Lidl announced a big change to its loyalty card scheme. Now customers collect points rather than reward coupons; £1 spent equals one point. This brings the scheme into line with both Nectar and Clubcard.

The discounts offered by loyalty cards may sound good, but that's only if you can access them. Our research has found that millions of people can't access loyalty promotions because they aren't eligible to join the supermarket schemes due to their age, lack of address or difficulties with digital access. 

Earlier this year, Tesco announced a new Clubcard for 16 and 17-year-olds. The move comes after a major Which? campaign urging supermarkets to lift unfair restrictions on their loyalty schemes so more people can take advantage of lower prices. 

Although this is a win for consumers, more work is needed as certain restrictions continue to lock people out of valuable savings. Groups often affected include under-18s and those without smartphones, who may struggle – or simply not know how – to access loyalty prices.

• Find out more: loyalty schemes compared

What has happened to the longer list?

We no longer publish research on the longer list of groceries as part of our monthly cheapest supermarket analysis, which included more branded items as well as own-brand items.

Instead, each month we publish our research on the cheapest supermarket for branded groceries separately, which we think will be of more use to shoppers as it will allow us to make more granular price comparisons. 

This new monthly tracker won't include Aldi and Lidl, as they don’t stock the same range of branded goods as the non-discounter supermarkets.

• Interested in more than just price? Shoppers have rated product quality, customer service, online deliveries and more to reveal the best and worst supermarkets.

What's happening to grocery prices?

 The UK inflation rate rose to 2.9% in the year to July, up from 2.8% in June, according to the Office for National Statistics (ONS). 

Grocery inflation, however, eased to its lowest since October 2024 in August. It stood at 2.1% in the four weeks until 9 August, according to Worldpanel by Numerator. This is down from 2.6% in the previous month and 3% the month before that. 

UK food inflation has not reached the levels forecast earlier in the year, amid fierce supermarket competition, shoppers' resistance to further price rises and better hedging by suppliers. The data showed that shoppers spent an average of £410 on groceries over the four weeks – £14.24 less than the previous period.  

Shoppers also turned to promotions to keep costs down, with 31.3% of sales involving a deal last month – the highest level this year. Meanwhile, the premium own-label sales growth returned to double figures for the first time since March, at 11.1%. Overall, 96m shopping trips included a value own-label product during the period.  

• Find out more: check what's happening to prices by supermarket, food category and range, using the Which? food and drink inflation tracker.

How Which? finds the cheapest supermarket

We check the prices of hundreds of grocery items at eight major supermarkets, using an independent price comparison website. 

For each supermarket, we calculate the average price of each item across the month, then add those up to get each supermarket's average total price. 

What items are on the list?

Our shopping list comprises the country’s most popular and widely available groceries, based on extensive market analysis. 

It includes branded items such as Cathedral City cheddar and Hellmann's mayonnaise, as well as own-brand products like potatoes and baked beans. 

Own-brand items won’t be identical across supermarkets, but we’ve ensured everything we’ve compared is as similar as possible, based on several factors, including quality and weight.

Which? never shares the full list of products used in its analysis, to avoid supermarkets attempting to skew the results. 

We don't want supermarkets to compete with one another to lower prices only on the items they know they'll be judged on. Instead, we want retailers to work to make groceries affordable across the depth and breadth of their available lines.

What about special offers and loyalty prices?

We include special offers but not multibuy discounts. 

We can only include loyalty prices that apply to all members of a scheme (where there's one price on the shelf for shoppers with a loyalty card and another for those without). Currently, this type of two-tier pricing is used at Lidl, Morrisons, Sainsbury's, Tesco and Waitrose. 

We're unable to include discounts that are personalised to selected members, and we can’t factor in points or other rewards, as these vary between customers and don't always have a quantifiable monetary value.

• Find out more: how to spend less at the supermarket.