We compared the prices of 39 popular groceries in April and found that the total average cost was £69.99 at Aldi - that's just 65p less than at nearest rival Lidl.
When we looked at a trolley packed full of 135 items, Asda was the cheapest non-discounter supermarket - in fact you could save £38.76 by shopping there rather than Waitrose.
Read on to find out how your supermarket compares in the analysis.
Cheapest supermarket for a basket of groceries
Every day in April, we checked the prices of 39 popular grocery items, including Heinz baked beans, milk and tea bags, at some of the UK's biggest supermarkets to see how they compare.
The chart below shows how much our basket cost on average:
Aldi was the cheapest overall, with our shop costing £69.99, beating rival discounter Lidl by just 65p - a slightly larger gap than last month, when it was just 25p. It's the 11th month in a row that Aldi has been the cheapest supermarket.
The same shop at Waitrose was £87.33 on average, making it £17.34 - that's 24.7% - more expensive than Aldi.
Of the 'big four' supermarkets, Sainsbury's was the cheapest at £76.85.
Find out more:How do bigger shopping lists compare?
We also compared the cost of a larger trolley of 135 items (the original 39, plus 96 more).
This trolley included more 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 cost the least, continuing its long-running streak (which started in January 2020) as the cheapest 'traditional' supermarket. It cost £343.46, on average, for our big trolley shop, beating next-cheapest Sainsbury's (£353.96) by £10.50.
Waitrose was £38.76 more expensive than Asda, coming in at £382.22 for the same trolley of goods.
Find out more: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 trolley price. To keep things fair, we include special offers, but we don’t count multibuys or loyalty scheme discounts.
Our shopping list includes branded items such as 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.
Find out more:What's happening to grocery prices?
The latest results from Which?'s food and drink inflation tracker show supermarket prices are continuing to rise, costing on average 17.2% more in March 2023 than a year previously. That's compared to 16.5% the previous month. However, some items rose far more: the prices of cheddar cheese, white bread and porridge oats were up by as much as 80%, for example.
The tracker - which checks more than 25,000 food and drink prices across the UK's eight biggest supermarkets - also shows own-label budget items, which are still the cheapest overall, were up 24.8% in March compared with the same time last year.
This is more than standard supermarket own brands, which were up by 20.5%. Branded goods and premium own-brand ranges meanwhile were both up 13.8%.
Find out more:Campaign update: supermarkets must do more
We sent a team of mystery shoppers into 123 different-sized branches of Asda, Morrisons, Sainsbury's and Tesco across the UK to assess the availability of a range of essential budget groceries. Each shopper was armed with a list of around 30 different basic budget groceries to find in each store. The results revealed shoppers who rely on Morrisons Daily, Sainsbury's Local and Tesco Express stores cannot access a decent range of cheap, healthy food.
Which? believes supermarkets must do more to help their customers. Retailers should be making sure affordable basic ranges are available in all branches, including smaller convenience stores, as well as improving unit pricing (e.g. the price per 100g) on all products so that customers can work out the best value.
While some of the supermarkets have engaged with Which? as part of our Affordable Food For All campaign, none have committed to making any significant changes. Which? is now calling on supermarkets to act by providing the support people around the country desperately need in order to keep food on the table during the ongoing cost of living crisis.
Do you want to see your supermarket take action to support people through the cost of living crisis?source https://www.which.co.uk/news/article/which-was-the-cheapest-supermarket-in-april-2023-aUVjl6I2crhD