Is supermarket fuel lower quality?
No. Every litre of petrol and diesel sold at a UK forecourt has to meet the same legal standard:
- Petrol must meet BS EN 228
- Diesel must meet BS EN 590
These standards set the octane, sulphur content, ethanol or biodiesel content and other properties, and they apply equally to Asda, Tesco, Sainsbury's and Morrisons as to BP, Shell, Esso or Texaco. A supermarket can't legally sell fuel that falls below them.
In practice, much of the UK's fuel comes from a small number of refineries and import terminals, so the base fuel at a supermarket and a branded forecourt down the road can come from the same place.
So what's different?
Additives. Fuel companies blend in their own detergent and anti-corrosion additives at the terminal. Branded companies market their additive packages heavily, but all fuel sold in the UK contains additives, and the minimum standard is the same.
Premium grades. Products such as Shell V-Power or BP Ultimate are higher-octane fuels with extra cleaning additives. They can make a measurable difference in high-performance engines designed for them, but for most everyday cars the benefit is small compared with the extra cost.
Price. Supermarkets often use fuel as a reason to visit the store, so they tend to price it more keenly.
How much cheaper is supermarket fuel right now?
Based on live prices from 2,363 forecourts that publish open data, on 25 Oct:
| Average price | Unleaded (E10) | Diesel |
|---|---|---|
| Supermarkets (Asda, Tesco, Sainsbury's, Morrisons) | 173.3p | 198.3p |
| Other forecourts | 173.9p | 200.8p |
That's around 0.6p a litre on unleaded. These are national averages – near you, the cheapest forecourt might be a supermarket, an independent or a branded site, so it's always worth checking.
Does cheap fuel harm my engine?
There's no evidence that standard-grade supermarket fuel causes engine problems in a car designed for it. What matters more for your engine is using the right type of fuel (petrol or diesel, and E5 if your older car needs it) and keeping up with servicing.
How do I find the cheapest fuel near me?
Search your postcode or town on Motor Snappy. You'll see every forecourt nearby that publishes live prices, the cheapest unleaded and diesel highlighted, and how your area compares with the UK average.