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Which? reveals the cheapest supermarket of the year
Aldi was the cheapest supermarket of 2023, according to Which? analysis of thousands of grocery prices.
We check the cost of a basket of groceries at the UK's eight biggest supermarkets every day throughout the year, revealing the cheapest supermarket at the start of each month.
In 2023, Aldi was cheapest for 11 out of 12 months, beaten just once by Lidl, leading Which? to officially crown it the cheapest supermarket of the year.
Here, we reveal how all of the country's biggest supermarkets compare for pricing, plus which 'big four' grocer was cheapest for a bigger trolley of food and drink items.
Aldi crowned cheapest supermarket of 2023
Hot on Aldi's heels, Lidl was the second cheapest supermarket for 11 months last year, beating Aldi to the top spot for one month only in October.
The two are consistently close in our monthly basket comparison, with the price difference between them averaging just £1.33 across the year.
Waitrose was the most expensive supermarket for our smaller basket of groceries for every month of the year.
It was also the most expensive in our larger trolley analysis for every month except September, when Sainsbury's was priciest for the first time (for shoppers not using a Nectar card).
- Find out more: supermarket price comparison over time
Cheapest supermarket in December
For our final basket analysis of 2023, we compared the prices of 43 popular groceries including Cathedral City cheese, chopped tomatoes, apples and milk.
Aldi was the cheapest supermarket overall, at £74.83 on average. Lidl was second cheapest, at £76.74.
The chart shows how much the groceries cost on average at each supermarket.
Waitrose was nearly £20 more expensive than Aldi, with an equivalent basket of groceries coming in at £94.94.
When it came to the traditional 'big four' supermarkets, our comparison revealed that Asda was cheapest, at £84.41 - but Sainsbury's and Tesco were right behind it, coming in at £84.54 and £84.86 respectively.
- Find out more: how to spend less at the supermarket
Asda cheapest for a big trolley
We also compared the cost of a larger list of 131 items (the original 43, plus 88 more).
This larger-scale comparison included more branded groceries, such as Bird’s Eye frozen garden peas and McVitie's biscuits. As the discounters don’t always stock branded products, we were unable to include Aldi or Lidl in this comparison.
The chart shows how much our larger trolley cost on average at each supermarket:
Asda was the cheapest for our trolley, a title it's claimed every month since January 2020 except for July 2023, when Morrisons pipped it to the post.
Our trolley cost £326.77 at Asda, comfortably beating next-cheapest Morrisons by nearly £10.
Our analysis also found that Waitrose was £41.02 pricier than Asda on average, with our big shop costing £367.79 at the high-end supermarket.
- Find out more: best and worst supermarkets
The year of loyalty pricing
2023 was the year of the loyalty card, with supermarkets and other retailers ramping up their efforts to keep loyal customers coming back.
And it looks like member-only pricing, where those signed up to a loyalty scheme pay less than those who aren’t, is a fast-growing trend that’s here to stay this year.
Tesco now only offers promotions in the form of Clubcard prices, and Sainsbury’s rolled out a huge swathe of Nectar prices last year.
Morrisons brought back its Morrisons More loyalty scheme last year, which now includes exclusive lower prices for members.
In our larger analysis last month, Sainsbury’s was the second priciest for the third month in a row, followed by Tesco, for those shopping without a loyalty card.
Which? believes this may be due to an increased emphasis on loyalty pricing which appears to have pushed average prices up for those who aren't members of the schemes.
We don’t include loyalty prices in our supermarket price comparison as not everyone is eligible to join the schemes, and some choose not to do so due to concerns over data privacy.
- Find out more: loyalty cards compared
What happened to grocery prices in 2023?
It's been a year since Which? launched a food price inflation tracker, revealing the supermarkets and food categories with the fastest rising inflation.
Overall, inflation has begun to dip after reaching one of its highest levels in more than 40 years, according to the Office for National Statistics. But our tracker tells a more detailed story.
Annual inflation for the supermarket food and drink in our tracker dipped slightly again to 9.6% in the three months to 30 November 2023.
That's down from 11% in October, and significantly lower than its peak of 17% in the three months to the end of April 2023.
Biscuits and chocolate had the highest level of inflation for the three months September to November, up 16.1% and 16% respectively compared with the same period in 2022.
While year-on-year inflation is falling, it's worth bearing in mind that this time a year ago, prices were already substantially higher than they were a year before that.
In July we looked at a two-year period rather than just one year, and found that food prices in the three months to the end of July 2023 were 25.6% higher than they were in the same period in 2021.
How Which? compares supermarket prices
We look at the prices of hundreds of grocery items at eight major supermarkets every day throughout every month, using an independent price comparison website.
We calculate the average price of each item at each supermarket across the month, before adding those up to get stores' average prices for a basket and trolley of products.
To keep things fair, we include special offers but not multibuys or loyalty-scheme discounts in our analysis.
Our shopping list includes branded items such as Cathedral City extra mature cheddar and PG Tips teabags, as well as own-label products such as smoked bacon rashers and little gem lettuce.
As own-brand items aren't identical across supermarkets, we use experts to ensure everything we’ve compared is as similar as possible, based on several factors including quality and weight.
