We compared the prices of 79 popular grocery items and found that both Aldi and Lidl (with and without loyalty prices) were cheaper than shopping at Tesco with a Clubcard or Asda.
Read on to find out where was priciest, plus how the supermarkets compared for a much bigger list of 203 products.
Aldi prices beat Lidl Plus
Throughout March, we checked the prices of 79 popular branded and own-brand groceries, including Hovis sliced bread, milk and cheese, at eight of the UK's biggest supermarkets to see how they compared.
The table shows how much our shopping cost on average:
Find out more:What about a bigger shopping list?
When we looked at a much larger selection (203 items), including more branded groceries, there were bigger savings with the loyalty schemes.
Tesco with a Clubcard – which had loyalty prices on 89 of the items – was the second cheapest, followed by Sainsbury's with Nectar and Morrisons with More.
Waitrose was the most expensive again, at £573.15 - 15% more than Asda.
We couldn't include Aldi or Lidl here as they didn't stock all the branded items on our list.
For shoppers without a Nectar card, Sainsbury's was the second-most expensive after Waitrose.
Interested in more than just price?How much of a discount do loyalty cards give?
Based on our smaller list of products, having a loyalty card would save an average of 0.02% at Lidl, 1% at Morrisons, 2% at Tesco and 5.5% at Sainsbury's over the month.
For our longer list, which included more branded groceries and a bigger selection of items with loyalty discounts, the savings were much more substantial – 2% at Morrisons, 7% at Tesco and 8% at Sainsbury's.
But you'd save even more money by switching to Aldi.
We think some supermarkets could do more to ensure certain groups of shoppers, such as those without a smartphone or those who are under 18, can access – or know how they can access – loyalty prices.
Find out more:What's happening to grocery prices?
Annual grocery price inflation rose slightly to 3.5% in the four weeks to 23 March, according to market analysts Kantar.
Prices are rising faster for items such as chocolate, butters and spreads, and chilled smoothies and juices. They are falling fastest for dog food, cat food, and household paper products such as toilet and kitchen roll.
Find out more:How Which? compares supermarket prices
We check the prices of hundreds of grocery items at eight major supermarkets, using an independent price comparison website.
For each supermarket, we work out the average price of each item across the month, then add those up to get each store’s average price.
Our shopping list comprises the country’s most popular and widely available groceries based on extensive market analysis.
It includes branded items such as Cathedral City cheddar and Hellmann's mayonnaise, as well as own-brand products such as potatoes and baked beans.
Own-brand items won’t be identical across supermarkets, but we’ve ensured everything we’ve compared is as similar as possible based on several factors, including quality and weight.
We include special offers but not multibuy discounts.
We are only able to take into account loyalty prices that apply to all members of a scheme (where there's one price on the shelf for shoppers with a loyalty card and another for those without). Currently, this type of two-tier pricing is used at Lidl, Morrisons, Sainsbury's, Tesco and Waitrose.
We are unable to include discounts that are personalised to selected members, and we can’t factor in points or other rewards as these vary from customer to customer and don't always have a quantifiable monetary value.
Find out more:source https://www.which.co.uk/news/article/cheapest-supermarket-in-march-has-aldi-beaten-lidl-aTKyB1Y18F3u