Supermarket vs branded fuel: is there a difference?
Supermarket fuel has a reputation for being the cheap stuff. The price part is usually true. The quality part mostly is not. Here is what you are and are not paying for.
Updated 2 October 2026 · Written by the Fuel Finder UK team
The same standard applies to everyone
Petrol sold in the UK must meet BS EN 228 and diesel must meet BS EN 590. That covers octane or cetane rating, sulphur content and the rest of the specification. A supermarket cannot sell fuel below it, and a major oil brand's standard grade is built to the same rulebook.
Much of the base fuel also comes from the same refineries and terminals. What changes is the additive package each retailer has blended in before it reaches the forecourt.
So what is different?
Additives. Every retailer adds detergents to keep the engine clean. Oil brands promote their own recipes and say they clean better. Supermarkets add them too, with less marketing. Independent proof that one standard-grade recipe beats another in normal driving is thin.
Premium grades. Higher-octane petrol and premium diesel are a real step up in specification, and several supermarkets sell their own. Whether your car benefits depends on the engine. If the handbook does not ask for it, you are unlikely to feel it. See E10 vs E5 petrol.
Price. This is the difference you will notice.
What today's prices show
On 2 October 2026, supermarket forecourts (Asda, Tesco, Morrisons and Sainsbury's) averaged 173.7p a litre for petrol and 198.2p for diesel. Everyone else averaged 175.1p and 200.5p. That is 1.4p a litre on petrol, about 77p on a 55-litre fill.
The gap is smaller than many drivers assume, and the brands are not in a neat order. On the same day Tesco was the cheapest named brand and BP the dearest, but two oil-company brands, Texaco and Jet, averaged less than Asda and Sainsbury's. See today's prices by brand.
Why the gap has narrowed
Supermarkets used to treat cheap fuel as a way to pull shoppers in, and they still sell huge volumes. But the Competition and Markets Authority's 2023 road fuel market study found that competition between retailers had weakened and supermarket fuel margins had risen. It recommended an open price data scheme so drivers could compare forecourts easily. That scheme is the data this site and app run on.
Where the real saving is
Brand averages hide the thing that matters: the station down your road. The same brand can be several pence apart between two towns, and an independent on a competitive stretch can undercut the supermarket next door. A couple of pence between brands is small beside the spread between the cheapest and dearest stations in most areas.
So pick on price and convenience, not the sign. Check average prices in your town, or read how to find the cheapest petrol near you.
Quick answers
Is supermarket fuel bad for your car?
No. It has to meet the same British Standards (BS EN 228 for petrol, BS EN 590 for diesel) as fuel from any other UK forecourt.
Which supermarket has the cheapest fuel?
It changes. On 2 October 2026 Tesco had the lowest average petrol price of the four big supermarkets and Asda the highest. Today's order is on the prices by brand page.
Is premium fuel worth it?
Only if your engine is designed for it or the handbook recommends it. For most everyday cars the standard grade is the better value.
Can I switch between supermarket and branded fuel?
Yes. You can mix fuel of the same grade from different retailers freely.
For live prices near you, Fuel Finder UK lets you sort stations by price or distance and filter by fuel grade and brand.