Asda is typically the cheapest supermarket for petrol in the UK. It has been the most consistent price aggressor among the big four since the Competition and Markets Authority's 2023 investigation, and it undercuts the national average by 4–7p/litre on average (Competition and Markets Authority, 2024).
But the answer changes by location. All four supermarkets price differently at individual stations based on local competition, and the cheapest option near you may not be Asda. The only reliable way to find the actual cheapest station near you right now is to check live prices before you leave.
Key Takeaways
- All four supermarkets consistently undercut the national average by 3–7p/litre (RAC Fuel Watch, 2026)
- Asda has the most aggressive national pricing; Tesco is closest in volume terms
- Individual station prices vary — the cheapest supermarket overall may not be cheapest near you
- Supermarket loyalty schemes (Clubcard, Nectar) offer fuel vouchers worth 2–5p/litre for regular shoppers
- The gap between the cheapest supermarket and a motorway service station is typically 20–30p/litre
How supermarket petrol pricing works
All four supermarkets source fuel from shared UK refineries and distribution networks. The base product is identical — the same crude-oil derivative, meeting the same BS EN 228 standard (UK Petroleum Industry Association, 2024). What differs is the retail margin each chain applies.
Supermarkets use fuel as a footfall and loyalty driver. Low fuel prices bring customers to the forecourt, who then spend in the attached store. This retail logic has historically kept supermarket margins tighter than branded stations.
The 2023 CMA investigation found that supermarkets had been "slow to pass on wholesale cost reductions" and recommended greater price transparency. Following the investigation, Asda in particular moved to more aggressive pricing to differentiate itself (Competition and Markets Authority, 2024).
Tesco vs Asda vs Sainsbury's vs Morrisons: head-to-head
| Asda | Tesco | Sainsbury's | Morrisons | |
|---|---|---|---|---|
| Typical price vs national avg | 4–7p below | 3–5p below | 3–5p below | 3–5p below |
| Forecourt sites (approx) | ~335 | ~600 | ~310 | ~340 |
| Loyalty scheme | Asda Rewards | Clubcard | Nectar | More Card |
| Fuel vouchers available | Yes | Yes (via Clubcard) | Yes (via Nectar) | Yes |
| Price leadership | Most aggressive | Large network | Competitive | Competitive |
Network figures approximate. Price differential is indicative; live prices vary by individual station and date.
Asda: the price aggressor
Asda has consistently positioned itself as the cheapest option since the CMA investigation. Its national average is typically 1–3p/litre below Tesco and Sainsbury's, with some individual stations pricing 5p below the next nearest competitor.
The Asda Rewards app allows customers to earn cashback on fuel, effectively increasing the value gap further for regular users.
Best for: drivers within range of an Asda and prioritising the lowest price.
Tesco: the largest network
Tesco operates the UK's largest supermarket forecourt network with approximately 600 sites. It prices within 1–2p of Asda nationally and often wins on pure location convenience, as there is simply a higher chance of a Tesco forecourt being nearby.
The Clubcard scheme is a genuine differentiator. Tesco periodically runs fuel voucher promotions where Clubcard points convert to fuel savings at 4–5x face value. A shopper earning £5 in Clubcard points can convert these to £20 in fuel vouchers during promotion periods.
Best for: drivers in urban areas where Tesco's network density is highest, and active Clubcard users.
Sainsbury's: competitive with Nectar upside
Sainsbury's prices are typically within 1p of Tesco's national average. Its network (~310 sites) is smaller, but heavily weighted toward larger out-of-town stores where forecourt investment is higher.
The Nectar scheme offers fuel vouchers to regular grocery shoppers. Sainsbury's often promotes double Nectar points on fuel, effectively reducing the net cost by 2–3p/litre for active scheme users.
Best for: regular Sainsbury's grocery shoppers who accumulate Nectar points.
Morrisons: competitive but limited network
Morrisons prices closely track Sainsbury's and Tesco. Its forecourt network (~340 sites) is concentrated in northern England and Scotland, which is a meaningful factor for drivers in those regions — Morrisons forecourts are often the cheapest option in areas where Asda coverage is sparse.
The More Card loyalty scheme provides fuel vouchers for grocery spend, similar to Clubcard and Nectar.
Best for: drivers in northern England and Scotland where Morrisons has strong coverage.
The loyalty scheme comparison
For regular grocery shoppers, fuel vouchers from loyalty schemes can materially reduce the effective price per litre. Here is how the four schemes compare:
| Scheme | Earn rate on groceries | Typical fuel voucher value |
|---|---|---|
| Tesco Clubcard | 1p per £1 spend | Up to 4–5p/litre during promotions |
| Sainsbury's Nectar | 1p per £1 spend | 2–3p/litre (double points events) |
| Asda Rewards | Cashback-based | 1–2p/litre effective |
| Morrisons More Card | Points-based | 1–2p/litre effective |
Tesco's Clubcard promotion structure delivers the highest fuel saving per pound of grocery spend when promotions are active, making it the best loyalty scheme for fuel in absolute terms.
Does it matter which supermarket's fuel you use?
All UK fuel meets the same EN 228/590 minimum standards, regardless of retailer. There is no meaningful quality difference between Tesco, Asda, Sainsbury's, or Morrisons petrol for a standard petrol or diesel car.
None of the four supermarkets sell "premium" fuels (V-Power, Ultimate, etc.). If you are interested in premium fuel, you would need to use a branded station.
How prices change day to day
Supermarket fuel prices are not fixed. All four chains adjust station prices multiple times per week, typically tracking wholesale price movements with a lag of 3–7 days. During periods of falling wholesale costs, supermarkets have historically been slower to reduce prices than to raise them — a pattern the CMA specifically highlighted (Competition and Markets Authority, 2024).
Tuesday and Wednesday are consistently the cheapest days of the week to fill up, as stations reset pricing after weekend demand peaks.
How to find the cheapest station near you
National averages give you a baseline, but individual station prices in your area may look quite different. A Morrisons in a rural area with no nearby competition may price differently from a Morrisons forecourt in a suburban high street with two other supermarkets within half a mile.
PetrolPal tracks live prices from stations across the UK. Before your next fill, check which station near you is actually cheapest today — the difference within a 2-mile radius is commonly 10–20p/litre.
Price data and network figures are approximate. Supermarket pricing changes daily — check live prices for current rates near you.