Each month, Which? analyses the price of food, drink and household essentials at the UK’s major grocers to reveal the cheapest supermarket of the month.
We compared the prices of 74 branded and own-label items at Aldi, Asda, Lidl, Morrisons, Ocado, Sainsbury’s, Tesco and Waitrose every day in August.
We tracked the prices of everything from semi-skimmed milk and free-range eggs to Hovis wholemeal bread and Knorr vegetable stock pots to work out which supermarket was the cheapest, on average, across the month.
There was a huge difference between the cheapest supermarket, where the trolley of goods would have cost £66.45, and the priciest, where you would have paid £105.25.
So, where did August shoppers get the best value for money? Which? reveals all below.
How do the cheapest and most expensive supermarkets compare?
The cheapest supermarket in August was Aldi, according to our research.
Here’s how much our trolley of 74 items cost, on average, at each of the UK’s biggest supermarkets:
Unsurprisingly, the discounters were the cheapest for our trolley of groceries, with Aldi coming out cheapest overall at £66.45. Lidl was just behind with the same items adding up to £67.17.
Asda was the cheapest ‘big four’ supermarket, with our trolley rolling in at £74.12.
Upmarket Waitrose was more than £38 more expensive than Aldi at £105.25 for the same items.
How do bigger shopping lists stack up?
We also compared a trolley packed to the brim with 165 items (the original 74 items, plus 91 more). This included a greater selection of branded items, such as Branston baked beans and Flash cleaning spray, not typically available all year round from the discounters – hence Aldi and Lidl not appearing in this chart.
Asda, at £256.31, was by far the cheapest supermarket in our larger analysis – it was £15.41 cheaper than its nearest rival Tesco. Compared with priciest supermarket Waitrose (£322.87), Asda shoppers could have saved an eye-watering £66.55.
Asda was also the cheapest major online supermarket when we checked in July.
- Find out more: supermarket pricing over time
How Which? compares supermarket prices
We tracked the prices of 74 items at the UK’s eight biggest supermarkets through August.
For our larger trolley analysis we added a further 91 items for all supermarkets apart from Aldi and Lidl, where the products were unavailable.
Our shopping list combined branded items, such as Kenco Millicano coffee, Oxo stock cubes and Twinings English breakfast tea, with own-label products including pasta, lettuce and milk.
Of course, own-brand items aren’t exactly the same at different supermarkets, but we’ve used experts to ensure that the products are as comparable as possible based on a range of factors including weight, quality and other industry data.
Using an independent price comparison website, we calculated the average price (including special offers but not multibuys) for each item throughout the month. We added those individual averages together to give an overall price for the trolley at each shop for the month.
What will M&S’s arrival at Ocado mean for next month’s price wars?
On 1 September, it was all change at Ocado as the online-only supermarket officially ended its nearly 20-year partnership with Waitrose, replacing it with fellow upmarket retailer Marks & Spencer.
The switch didn’t go swimmingly, though, with Ocado customers taking to Twitter to complain of cancelled orders on the day of the M&S launch. And to deal with a surge in demand, Ocado temporarily suspended deliveries to its employees in order to clear some of the backlog.
Before Waitrose disappeared from the Ocado website we checked the prices of 30 grocery items to see whether M&S or Waitrose-branded products were cheaper. Check out our story, will your Ocado shopping be cheaper now M&S products have replaced Waitrose?, for the results.
And to find out whether the switch from Waitrose to M&S affects Ocado’s place in our overall supermarket price rankings, you can check back here at the beginning of October.