Which supermarket was cheapest in May 2015?Which? compares prices of everyday groceries

07 June 2015


Asda was cheapest for our supermarket comparison in May 2015

Waitrose was the most expensive supermarket for our price comparison basket in May 2015, charging £13.78 more than the least expensive supermarket.

Every month we compare the price of between 70 and 100 food and grocery products to find out the cheapest supermarket for our basket. This month, Asda charged £127.53 for 74 items - Waitrose charged £141.31.

Our analysis found that Asda was cheaper for a range of products. This included selling 200g of Kenco instant coffee for £2.97, when the other supermarkets were selling it for more than £4.50 and one for as much as £6. 

Asda also sold 850g of Dorset cereal for £2 - the next cheapest supermarket sold it for £2.48.

To see the full results for this month and the previous year, and to find out how your local supermarket did, go to supermarket prices compared.

Supermarkets in May

Sainsbury's announced its first annual profit fall in a decade. This was partly due to write-downs on property (reducing how much you say a property is worth because it's now worth less) and partly due to an ongoing programme of price cuts. 

Morrisons, by contrast, saw its first quarterly rise in sales in the 12 weeks to 24 May, according to market share figures published by consumer researcher Kantar Worldpanel.

But what do customers of Sainsbury's and Morrisons really think about these supermarkets, and how do they compare to the discounters Aldi and Lidl? The results of our supermarket survey reveal all - go to the best and worst supermarkets.

Supermarket price comparison schemes

Supermarkets use price matching schemes - often giving you a voucher if your shopping would have been cheaper elsewhere. However, these schemes do vary - we've put what the major ones are below:

  • Asda checks prices against Morrisons, Tesco, Sainsbury's or Waitrose and it will give you a voucher for the difference if it isn't 10% cheaper
  • Morrisons compares against Aldi, Asda, Lidl, Sainsbury’s and Tesco and gives you the difference in points
  • Sainsbury's has a price match for branded items only and compares against Asda
  • Tesco checks your prices against Asda, Morrisons and Sainsbury’s and will give you a voucher for the difference if it's cheaper elsewhere
  • Waitrose price matches Tesco on branded items and these are the prices it sells for.

Which?'s price comparison basket

Every month we compare the price of between 70 and 100 grocery items at the main online supermarkets Asda, Morrisons, Ocado, Sainsbury's, Tesco and Waitrose. 

We use data from the independent shopping website Mysupermarket and average the prices over the month, including discounts but not multibuys. 

The products are all branded items and include a wide range of groceries - from cereal to jam, and from beans to bread.

More on this...

  • Discover how Sainsbury's customers rate it with Sainsbury's survey results
  • Read about Best Buy food and drink in our gallery of taste test winners
  • Find out if loyalty cards are worth it on our supermarket loyalty cards page