Is Supermarket Fuel Cheaper?

Yes, but by less than most people assume: about 3p a litre. Across the forecourts we track, the four big supermarkets average 159.1p for unleaded against 162.1p for the oil majors. That is £1.65 on a 55-litre fill - worth having, but smaller than the gap between the best and worst station in most towns.

The actual numbers

The four supermarkets sit within 1.0p of each other. The interesting gap is not between them - it is between the supermarket cluster and Shell at the other end, 11.2p away. Full current figures are on our fuel prices by brand page.

Costco is cheaper still, with conditions

At 153.7p Costco averages 5.4p below the supermarket average. But there are only 22 sites in the country, membership is required, and queues are common. For most drivers it is not a realistic weekly option.

Why the supermarket advantage is smaller than it used to be

Supermarkets historically used fuel as a loss leader to drive store visits. The Competition and Markets Authority found in its road fuel market study that supermarket fuel margins had increased materially, and that the competitive pressure supermarkets once applied to the wider market had weakened.

Is the fuel itself any different?

No, for standard grades. All petrol sold in the UK must meet BS EN 228 and all diesel BS EN 590. Supermarket fuel comes from the same refineries and often the same terminals as branded fuel - frequently delivered by the same tankers.

The genuine difference is additives. Branded premium grades - Shell V-Power, BP Ultimate, Esso Synergy Supreme+ - contain higher detergent doses that manufacturers say help keep injectors clean. Whether that is worth 10p a litre to you depends on the car, but for a standard engine on standard fuel there is no quality gap.

The comparison that actually matters

Choosing a supermarket over an oil major saves you around 3.0p. Choosing the cheapest station near you over the dearest usually saves 8p to 12p. The second decision is worth roughly three times the first, and it is the one people skip.

Check what is actually cheapest around you on findpetrol, or browse prices by region and town.

Frequently asked questions

Is supermarket fuel bad for my engine?

No. It meets the same British Standard as any other fuel sold in the UK. This is a persistent myth with no basis in the specification.

Which supermarket is cheapest?

Nationally they are within 1p of each other, so the answer locally depends on your specific stores rather than the chain. Tesco averages 158.8p and Asda 159.8p, but a single site can sit either side of that.

Is Costco worth joining for the fuel alone?

At 5.4p below the supermarket average, a 55-litre fill saves about £2.97. You would need roughly 11 fills a year to recover a standard membership fee on fuel alone - achievable for a regular driver with a nearby site, but there are only 22 of them.

Does premium fuel give better mpg?

Not in an engine designed for standard fuel. Any economy gain is generally too small to offset the price difference. Some high-performance engines do specify higher octane, in which case follow the manual.

Figures updated 29 August 2026. Averages calculated across all UK sites we track for each brand via the CMA open fuel price scheme - 513 Tesco, 405 Asda, 341 Morrisons, 314 Sainsbury's, 1,448 Esso, 1,076 BP, 910 Shell. Brand averages move daily; the live table is on our brand page.