Lidl was the cheapest supermarket in May, according to Which?’s latest monthly price analysis.
We compared prices for a basket of 18 popular grocery items each day during the month of May. Our price tracking found that, on average, shoppers would have paid £23.55 for the basket at Lidl – £1.05 cheaper than rival discounter Aldi.
The most expensive supermarket was £8.30 pricier than Lidl for an equivalent basket of groceries.
Here, we reveal the cheapest and most expensive supermarkets of the month.
Every day in May, we checked the prices of 18 popular groceries, including seedless grapes, white bread, and tea bags, to compare supermarkets with each other.
The table below shows how much our basket cost on average:
Lidl was the cheapest, with the basket costing £23.55 on average. Aldi was £1.05 pricier at £24.60.
We don’t compare the same items each month due to changes in product availability, but this is the sixth month in a row Lidl has been the cheapest supermarket.
Of the ‘big four’ supermarkets, Asda was the cheapest, with the basket costing £26.28.
The most expensive supermarket for this basket was Waitrose, at £31.85 – £8.30 more than Lidl.
We also compared costs from a larger trolley of 59 products (the original basket plus 41 more).
This trolley included a larger number of branded items, such as Andrex toilet paper and Cathedral City cheese. You can’t always find these items in discounter supermarkets, so we haven’t included Aldi or Lidl in this comparison.
Asda was the cheapest supermarket for this trolley, continuing its streak as the cheapest traditional supermarket that started in January 2020. It cost £129.53 on average for this trolley of items, that’s £3.94 cheaper than its nearest rival Sainsbury's.
At Waitrose, the bill would have been £13.08 more than Asda, coming in at £142.61.
We look at the prices of hundreds of grocery items at eight major supermarkets every day throughout the year using an independent price comparison website.
For each superstore, we work out the average price for each item across the month. Then we add those up to get each store’s average trolley price. To keep things fair, we include special offer prices but we don’t count multibuys.
Our shopping list includes branded items like Heinz Baked Beans and Dolmio sauce, as well as own-brand products like apples and lettuce. Own-brand items won’t be identical across supermarkets, but we’ve used experts to ensure everything we’ve compared is as similar as possible, based on a number of factors including quality and weight.
We’re not the only ones comparing imaginary shopping baskets each month. The Office for National Statistics (ONS) announced inflation reached in April, based on a ‘basket’ of around 700 popular goods and services.
A Which? analysis of 21,000 groceries across two years found that the average product had risen in price by 3.14%. But this masked major rises for some specific items.
Some 265 grocery products had inflation of over 20%. This included Kellogg’s Crunchy Nut Corn Flakes (500g), up 21.4% at Tesco. And own-brand closed cup mushrooms (250g), up 21.4% at Asda.
In a separate analysis, the ONS looked at pricing data for 30 everyday grocery items to see how the prices of low-cost products have changed.
Though it describes its research as ‘highly experimental’, the ONS found that low-cost pasta increased by 50% when comparing April 2022 to April 2021. The next biggest increases were for crisps (17%), bread (16%) and minced beef (16%).