Which was the cheapest supermarket in January 2024?

In our first monthly comparison of 2024, Aldi has continued its reign as the UK's cheapest supermarket, with Lidl close behind. 

We compared the prices of 72 popular grocery items in January and found that the total cost would have averaged £129.24 at Aldi – £3.13 less than at Lidl. 

Read on to find out how your supermarket compares in the analysis. 

Waitrose remains priciest supermarket

Every day in January, we checked the prices of 72 popular groceries, including Heinz baked beans, milk and cheese, at the UK's eight biggest supermarkets to see how they compare.

The chart below shows how much our shopping cost on average:

Aldi was the cheapest overall, with our shop costing £129.24 on average, beating rival discounter Lidl by just £3.13. 

The same shop at Waitrose was £170.44 on average, making it £41.20 – or 32% – more expensive than Aldi.

Of the 'big four' supermarkets, Asda was the cheapest at £145.75.

Of course, price is just one factor when you're deciding which supermarket to shop at. We also survey shoppers on their experiences in terms of 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.

This month we've refreshed the master list of groceries we use to make sure it continues to reflect the most popular groceries.

• Find out more: supermarket price comparison over time

What's happening to grocery prices?

The latest results from the Which? food and drink inflation tracker show the price of some everyday groceries has more than doubled over the past year. 

We analysed inflation on more than 25,000 food and drink products to see how everyday product prices are being affected.

Annual inflation for the groceries in our tracker dipped slightly to 8.5% in the three months to 31 December 2023. That's down from 9.6% the previous month, and significantly lower than its peak of 17% in the three months to the end of April 2023.

Chocolate, biscuits and crisps are the three types of groceries rising in price fastest. But the good news is inflation on other types of food, such as butters and spreads, has dropped significantly over the past few months. 

• Find out more: Which? food and drink inflation tracker

Clearer pricing calls move forward 

Which?'s Affordable Food For All campaign is calling for clearer grocery pricing and more budget groceries in convenience stores.

Last month, it was revealed that the Price Marking Order (PMO), which sets out the rules for unit pricing (the price per 100g or 100ml), will be reformed.

The Department for Business and Trade said the proposed changes would ensure unit pricing was more consistent, better helping shoppers compare like-for-like in order to work out the best value.

Meanwhile the Competition and Markets Authority has published a short guide for shoppers on unit pricing.

• Do you want to see your supermarket take action? Sign our petition