Are Supermarkets Still the Cheapest for Petrol in 2026?

For years, the advice has been simple: fill up at a supermarket and you will pay less than anywhere else. That advice is still broadly true in 2026, but the picture is more complicated than it used to be. Asda has lost its crown as the cheapest supermarket, retailer margins have more than doubled since 2017, and the difference between the cheapest and most expensive supermarket station near you can be greater than the difference between a supermarket and a branded station. Here is what the data actually shows.

3-7p

Typical saving per litre at supermarket forecourts vs national average (RAC Fuel Watch, 2026)

8.4%

Average supermarket fuel margin in H1 2025, more than double the 4% level in 2017 (CMA)

2.1p

Amount Tesco, Morrisons and Sainsbury's were cheaper than Asda per litre, according to recent RAC analysis

Are supermarkets still the cheapest option?

Yes, generally — but with important caveats. According to RAC Fuel Watch data from 2026, all four major supermarkets consistently undercut the national average by 3-7p per litre. At current petrol prices of around 149.80p per litre nationally, the supermarket average of approximately 143-147p represents a saving of £1.65-3.85 on a 55-litre fill-up. (source)

However, the gap between supermarkets and branded stations has narrowed compared to pre-2022 levels, and the CMA has expressed concern that supermarket margins — which they can observe directly through confidential data from retailers — have remained elevated. Supermarket fuel margins averaged 8.4% in H1 2025, more than double the 4% level seen in 2017.

Asda is no longer automatically the cheapest

For most of the past decade, the conventional wisdom was clear: if there is an Asda nearby, fill up there. Asda positioned itself as the price leader and other supermarkets broadly followed. That dynamic has changed.

According to RAC analysis of CMA data, Tesco, Morrisons and Sainsbury's were selling petrol for an average of 2.1p less per litre than Asda, and diesel for 2.5p less per litre. The RAC noted that "Asda has lost its claim to being the cheapest supermarket for fuel."

The CMA's own 2023 market study identified the root cause: in 2022, Asda and Morrisons each separately made a decision to target higher margins on fuel. Other retailers, rather than competing aggressively, raised their prices in line with these changes. The CMA stated this "indicates that competition has weakened."

Asda has since moved to more competitive pricing again following the CMA investigation and continues to be among the cheapest options. But the assumption that Asda is always cheapest no longer holds — and the difference between supermarkets at any given location can be larger than the difference between supermarkets and some branded stations.

The same supermarket charges different prices at different sites

A common mistake is assuming every branch of a supermarket charges the same price nationally. They do not. Supermarket forecourt pricing is set locally based on competition, operating costs and demand. A Tesco in a rural area with no nearby competition may price 5-8p higher than a Tesco in an urban area surrounded by competing forecourts.

This is why checking the actual price at your specific local supermarket — rather than assuming it is cheaper because it is a supermarket — is important. Our live fuel price map shows the current price at every station including all four major supermarkets, updated every hour from the Government's Fuel Finder data.

Supermarket loyalty schemes add value beyond the pump price

The headline pump price is not the only consideration. Supermarket loyalty schemes offer fuel-related benefits that effectively reduce the real cost per litre:

Tesco Clubcard: Clubcard points earned on fuel purchases. Occasional double-points promotions and fuel vouchers via Clubcard.
Sainsbury's Nectar: Nectar points on fuel. Regular promotions offering additional points per litre.
Asda Rewards: Cashback on fuel via the Asda Rewards app, effectively reducing the per-litre cost further for regular users.
Morrisons More: Points on fuel purchases redeemable against groceries.

For regular supermarket shoppers who fill up at the same chain, these schemes can add the equivalent of 1-3p per litre in value beyond the pump price.

How supermarket fuel compares to branded stations

The question of whether supermarket and branded fuel is identical in quality comes up regularly. The short answer is: the base fuel is the same, but branded stations add proprietary additive packages.

All petrol sold at UK forecourts must meet the BS EN 228 standard, regardless of whether it is sold by Tesco or Shell. The crude oil derivative is essentially the same product. What differs is the retail margin each chain applies and, for branded premium fuels, the additive packages claimed to improve performance and engine cleanliness.

Shell V-Power, BP Ultimate and similar products contain additional detergent additives not present in standard supermarket fuel. Whether these additives provide meaningful real-world benefit is disputed — most independent tests show negligible differences in fuel economy for normal driving. For high-performance vehicles or those with high-specification engines, manufacturer guidance is worth checking.

For the vast majority of drivers in standard petrol and diesel cars, supermarket fuel is chemically equivalent to branded standard fuel and significantly cheaper.

Which supermarket is cheapest near you right now?

Given that supermarket prices vary by location and change regularly, the only reliable way to know which is cheapest near you right now is to check live data. Our fuel price map shows every supermarket forecourt near you with its current price, updated every hour. Filter by fuel type and adjust the search radius to find the cheapest option for your specific location.

The cheapest station within 5 miles of you may not always be a supermarket — independent stations and some branded forecourts occasionally price below their supermarket neighbours, particularly in areas where competition is intense. Our Fuel Finder enforcement article explains why some stations show stale prices and how to spot them.

The bottom line

Supermarkets remain the best starting point for cheap fuel in 2026, but the picture is more nuanced than it was. Asda is no longer guaranteed to be the cheapest supermarket. Margins have risen across all retailers. And the cheapest option varies significantly by location. Checking live prices before you fill up — rather than assuming a particular brand or type of station is cheapest — is the most reliable approach.

Use our fuel cost calculator to work out how much you spend annually and how much you could save by consistently using the cheapest nearby station.