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Which supermarket was cheapest in May 2017?

The winning supermarket has topped our monthly supermarket price comparison for the first time in almost 18 months

Our monthly supermarket price comparison reveals that Tesco was the cheapest place to buy our basket of branded groceries in May. It’s the first time that Tesco has come out as cheapest in our price comparison for almost 18 months.

We check the prices of up to 100 branded groceries each month across six of the big supermarket chains, and more often than not, Asda comes out cheapest. But in May Tesco had a lot more special offers on its products than Asda, which meant that it was able to slightly undercut Asda’s basket price.

The average price for our basket of 74 common grocery items was £144.41 at Tesco, compared to £152.50 at the most expensive supermarket.

To see the full price comparison results, including Asda, Tesco, Sainsbury’s, Morrisons, Ocado and Waitrose, head to our supermarket prices compared page.

Supermarkets in the news in May

The impact of inflation and a weak pound is being passed on to shoppers in price increases, with the average household paying an extra £27 on groceries in the 12 weeks to May 21 – according to data revealed by research company Kantar.

The data showed that all supermarkets experienced a growth in sales, but Aldi and Lidl outpaced the big four (Asda, Sainsbury’s, Tesco and Morrisons) in their year-on-year growth at the fastest rate since January 2015. Supermarket sales were driven by a demand for healthier options, with sales of fresh produce up and sugar down compared to the previous year.

Another potential challenge to the big four supermarkets comes in the form of Amazon Go, Amazon’s futuristic checkout-free grocery store concept, which is set to launch in the UK soon. The store uses sensors and a smartphone app to detect which products you’ve left the store with and to calculate a bill charged to your Amazon account. Amazon’s first and flagship store is in Seattle.

How we compare supermarket prices

Each month, we start with a list of more than 100 popular products that are likely to be sold in all six supermarkets we cover (Asda, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose). The products range from Diet Coke to Nestle Shreddies and John West sardines.

Using data from the independent shopping website MySupermarket, we calculate the average price (including discounts, but not multibuys) for each item across a whole month. We add up those average prices to get the cost of the basket.

If a product hasn’t been sold in one or more of the six supermarkets during the month, then it’s removed from that month’s basket altogether to ensure a fair comparison. This month we included 74 items in the basket.

Supermarket price comparison schemes

Many supermarkets have a price-matching scheme, where they compare their prices against other supermarkets and give you a voucher for the difference if your shopping would have been cheaper elsewhere.

We’ve rounded up the differences between each scheme below. Click the links to find out how each supermarket compared in our customer satisfaction survey.

  • Asda will give you a voucher for the difference if your ‘comparable grocery shopping’ isn’t 10% cheaper than Morrisons, Sainsbury’s, Tesco and Waitrose.
  • Morrisons no longer has a price-match scheme.
  • Ocado price matches against Tesco and will give you a voucher for the difference.
  • Sainsbury’s no longer has a price-match scheme.
  • Tesco checks prices on branded products against Asda, Morrisons, and Sainsbury’s. Tesco will deduct the difference from the price of your shop before you pay at the till or online, so should charge the same as Asda for our basket. But you need to buy at least 10 items to qualify for the scheme.
  • Waitrose price matches Tesco on branded items. There aren’t any vouchers – it claims to sell these items at the same price.
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