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Which was the cheapest supermarket in May?
Aldi was the UK's cheapest supermarket in May 2024, widening the gap with second-placed Lidl.
We compared the prices of 69 popular grocery items in May and found the total cost would have averaged £121.56 at Aldi – £3.32 less than at Lidl.
Read on to find out how your supermarket compares in the analysis.
Waitrose still the most expensive supermarket
Every day in May, we checked the prices of 69 popular groceries, including Heinz baked beans, milk and cheese, at eight of the UK's biggest supermarkets to see how they compared.
The chart below shows how much our shopping cost on average:
Aldi was the cheapest overall: our shop cost £121.56 on average, meaning it beat rival discounter Lidl by £3.32.
The same shop at Waitrose was £158.13, making it £36.57 – or 30% – more expensive than Aldi.
Of the 'big four' supermarkets, Asda was cheapest at £137.91.
Of course, price is just one factor when you're deciding which supermarket to shop at. We also survey shoppers on product quality, customer service, store experience, online deliveries and a range of other factors to reveal the best and worst supermarkets.
- Find out more: how to spend less at the supermarket
How Which? compares supermarket prices
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 supermarket, we work out the average price for each item across the month, then we add those up to get each store’s average price. We include special offers, but we don’t count multibuys or loyalty-scheme discounts.
Our shopping list comprises the country's most popular and widely available groceries based on extensive market analysis.
It includes branded items such as Heinz baked beans and Dolmio sauce, as well as own-brand products such as apples and lettuce. Own-brand items won’t be identical across supermarkets, but we’ve ensured everything we’ve compared is as similar as possible based on a number of factors, including quality and weight.
- Find out more: supermarket price comparison over time
What's happening to grocery prices?
Grocery price inflation fell to 2.9% over the four weeks to May 12 – the 15th monthly drop in a row, according to market analyst Kantar.
It said sales of own-label groceries were still growing faster than branded ones. It means grocery inflation as a whole is now returning to more normal levels after the peaks of the past few years.
Lidl reached a new record-high market share of 8.1%, fuelled in part by its loyalty scheme, which has recently been revamped with Lidl launching loyalty prices for the first time.
- Find out more: Which? food and drink inflation tracker
