Aldi was the cheapest supermarket in March, according to the latest Which? analysis.
A trolley full of 108 groceries and household essentials cost £111 at the budget supermarket –- just £2 less than at Lidl, its closest rival.
But which of the traditional ‘big four’ supermarkets was cheapest, and where did shoppers pay the most?
Here, we compare supermarket prices across all the big names, and explain how we’ve changed our research to be able to include the discounters.
How do supermarket prices compare?
We checked the prices of more than 100 items, from own-brand yoghurts and vegetables to Head & Shoulders shampoo and Nutella chocolate spread, throughout March to see how UK supermarkets compared.
Of the larger supermarkets, Asda was cheapest, with shoppers paying £123 for an equivalent trolley of goods.
Sainsbury’s, which was the cheapest ‘big four’ supermarket in 2019, came in third-most-expensive last month. Customers’ shopping would have cost £144 there; however, this was only slightly more than at Tesco (£140) and Morrisons (£143).
Waitrose was by far the most expensive supermarket, charging £175 for an equivalent selection of goods – a whopping £64 more than Aldi.
Aldi and Lidl not always cheapest for branded products
While Aldi and Lidl offered the lowest prices overall, the discounters weren’t always cheapest for branded goods. Some of the greatest differences we found in average prices across March included:
- Head & Shoulders Classic Clean Shampoo (500ml)– £5.15 at Waitrose, £3.42 at Asda
- Knorr Vegetable Stock Pot (4 x 28g) – £1.49 at Aldi and Waitrose, 99p at Lidl
- Patak’s Madras Paste Pots (2 x 70g) – £1.60 at Morrisons, 99p at Aldi and Lidl
- PG Tips Pyramid Tea Bags (240) – £5.99 at Waitrose, £3.53 at Asda
Based on our results, it seems that if there are certain brands you would always choose over supermarket own-labels, it can pay to shop around.
- Find out more: supermarkets coronavirus latest
How do bigger shopping lists stack up?
We also compared prices for a larger trolley of 193 products (the original 108, plus 85 more). This included more branded items, such as Dolmio bolognese sauce and Fairy Platinum washing-up liquid.
We were unable to include Aldi and Lidl for this more in-depth price comparison due to the smaller and frequently changing range of branded goods they sell.
Here, Asda was cheapest by far at £295 – that’s £25 less than the next-cheapest option, Morrisons.
Waitrose was priciest again, at £376 – an eye-watering £81 more expensive than Asda.
Grocery prices at Morrisons, Sainsbury’s and Tesco have proved very close across both tests; here they are within just £7 of each other. So, while the order has changed slightly from the previous chart, the difference is actually only a few pounds.
- Find out more: best and worst supermarkets
How Which? compares supermarket prices
We tracked the prices of 108 items at the UK’s eight biggest supermarkets throughout March. We added a further 85 branded items to our analysis for all supermarkets except Aldi and Lidl, where the products were unavailable.
On our shopping list were own-brand items, such as milk chocolate digestives, honeydew melons and garlic bread, as well as branded items like Hovis wholemeal bread, Kenco Millicano coffee and Patak’s curry paste pots.
The extended trolley also included items such as Napolina chopped tomatoes, Flash bleach spray and Cadbury chocolate fingers.
Using data from 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.
- Find out more: how to store food safely during the coronavirus pandemic
How our research has changed to include Aldi and Lidl
At Which?, we’ve been analysing supermarket prices for years, but this is the first time we’ve included Aldi and Lidl. Why?
We used to only include branded products in our trolley. This had the advantage of ensuring that we were strictly comparing like with like. However, the downside was that as Aldi and Lidl primarily sell own-label items with just a small supplementary range of branded goods, they couldn’t be included.
Many Which? members told us that they would find it helpful to be able to see how the discounters compared with the mainstream supermarkets.
We listened to that feedback and have added own-label items to our trolley to enable us to widen the net of retailers we include. We 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.
This story is the result and we’d love to know what you think:
Should you choose a supermarket purely based on price?
For many people, price isn’t everything: customer service and the overall experience of being in the store can make a big difference, too.
And with grocery shopping recently affected in unprecedented ways due to coronavirus, extra factors will probably be influencing your choice of supermarket: proximity if you’re able to get to the shops, or the availability of online delivery slots if not (see below for more info on this).
If you’re lucky enough to have a choice right now, you might be interested to see which retailers Which? members have voted as the best online and in-store supermarkets.
Supermarkets’ reactions to coronavirus
The past month has been a whirlwind for the UK’s supermarkets, as the nation is forced to stay at home.
At Which? we’ve been working hard to provide advice about what’s going on with supermarket shopping. If you want to know more, check out the following guides:
- Supermarkets coronavirus latest, including opening hours for key workers and online delivery slots
- How to get food delivered to vulnerable households
- Safest ways to pay volunteers for your shopping
- How to stay safe in supermarket stores
- Analysis: the truth about grocery stockpiling