Why is supermarket fuel usually cheaper?
Supermarket forecourts are usually cheaper because they sell huge volumes of fuel and use low pump prices to bring shoppers to the store. Right now the average price of petrol at Tesco, Asda, Sainsbury's, Morrisons and Costco forecourts is 171.7p a litre, against 175.3p at every other forecourt. On a 50-litre fill that is a difference of £1.80.
How much cheaper is supermarket petrol?
The figures above come from live prices at 7,553 UK forecourts. The gap moves around from day to day, and it varies a lot by area. A supermarket in a town with several rival supermarkets nearby will often price more keenly than one with no competition for miles.
The Competition and Markets Authority (CMA), which monitors the fuel market, has repeatedly found that supermarkets are on average the cheapest places to buy fuel. In its 2023 market study it described them as generally the cheapest, with Asda typically the cheapest of those. Its June 2026 monitoring update said supermarkets remained, on average, the cheapest places to buy fuel and led the market on price.
Why can supermarkets sell fuel for less?
They sell a lot of it
A big supermarket forecourt can sell far more fuel than a typical village or roadside station. Fixed costs such as staff, rent and equipment are spread over many more litres, so the store can take a smaller margin on each one and still make money.
Fuel brings people to the shop
For a supermarket, the forecourt is part of a bigger business. A driver who stops for a cheap tank may also buy their weekly shop, and the profit on that basket matters more to the supermarket than a few pence on each litre. From time to time supermarkets also run offers that link money off fuel to spending in store or loyalty schemes.
They set the pace for local prices
Because supermarkets tend to be cheapest, other forecourts nearby often price against them. The CMA found that supermarket pricing has historically anchored prices in the wider market. When there is no supermarket in an area, or a supermarket has no supermarket competitor nearby, the CMA said prices are likely to be higher.
Is supermarket fuel always the cheapest?
No. Supermarkets are cheapest on average, which is different from being cheapest everywhere. Independent forecourts and some branded stations regularly undercut the local supermarket, especially where several stations compete on the same stretch of road.
Supermarket margins have also risen over time. The CMA's 2023 study found that average annual supermarket fuel margins increased by 6p a litre between 2019 and 2022. Its 2023 report also found that Asda's fuel margin target in 2023 was more than three times what it had been in 2019. The cheap-fuel reputation still broadly holds, but it is worth comparing before assuming.
Is supermarket fuel lower quality?
No. All petrol and diesel sold at UK forecourts has to meet the same legal fuel specifications, whoever sells it, tested against the British Standards for petrol (BS EN 228) and diesel (BS EN 590). Some brands add their own additive packages, especially in premium grades, but standard supermarket unleaded and diesel are fine for any car that runs on those grades.
Does the saving cover the drive?
Only if the supermarket isn't too far out of your way. A cheaper price a long drive away can be cancelled out by the fuel you use getting there. Our guide on whether it's worth driving further for cheaper fuel explains the maths. The simplest win is to fill up when you are already going to the supermarket.
Compare supermarket prices near you
Enter your postcode in our fuel price search to see supermarket and independent forecourts side by side, sorted by price, distance or best value once the drive is counted.
Sources
- CMA: plan to help drivers get more competitive fuel prices (2023)
- CMA: road fuel market monitoring update (June 2026)
- The Motor Fuel (Composition and Content) Regulations 2021
- Live prices: the UK government's Fuel Finder scheme, via Cheapest Fuel. Contains public sector information licensed under the Open Government Licence v3.0.