Costco vs Asda: which is cheaper?
Today’s head-to-head on price, network size and coverage, read live from every Costco and Asda forecourt reporting to the government Fuel Finder scheme.
Costco is cheaper today
Costco is averaging £1.62 a litre for petrol against £1.69 at Asda — 6.8p a litre, £3.74 on a 55-litre tank. On diesel the gap is 8.8p and Costco leads. These are medians across each whole network, so treat them as the shape of the market rather than a promise about the forecourt at the end of your road.
Head to head
Live across every reporting forecourt. Green marks the better figure.
| Measure | Costco | Asda |
|---|---|---|
| Petrol (E10)median across the network | 161.9p | 168.7p |
| Diesel (B7)median across the network | 182.9p | 191.7p |
| Super unleadedwhere sold | 172.4p | 187.8p |
| Cheapest forecourtlowest petrol price in the network | 154.9p | 157.7p |
| Dearest forecourt | 165.9p | 177.9p |
| Spread across sitesdearest minus cheapest | 11.0p | 20.2p |
| Forecourtscurrently reporting a price | 22 | 405 |
| Regions coveredof twelve UK regions | 9 | 12 |
| Motorway sites | 0 | 0 |
The row worth dwelling on is the spread. Costco sites range across 11.0p and Asda across 20.2p. Both are far wider than the gap between the two brands, which is the whole argument for checking the forecourt rather than trusting the sign — see what is actually near you.
How the gap has moved
Daily network averages for both chains, on one scale.
Where each brand actually is
Forecourts by UK region. A cheaper chain is only cheaper if it has a site near you.
Coverage shape explains most of what looks like a price difference. Fuel is cheaper in some regions than others regardless of brand, so a chain weighted towards the cheaper ones shows a lower national average without any of its sites pricing unusually. Compare the regions to see how large that effect is.
What you are choosing between
Ownership, loyalty and premium grades.
Members-only forecourts at warehouse clubs, routinely among the cheapest prices in the country.
The supermarket that made cheap fuel a national talking point, and still usually prices at or near the bottom of the table.
Which should you use?
On today’s numbers Costco wins the national comparison by 6.8p. Over a year of fortnightly fills that is £97 — real money, but less than the difference between a well-chosen and a badly chosen forecourt of either brand. The question that does decide it is distance. A litre saved is only worth having if you did not burn the saving getting there: the break-even calculation is a single division, and for most cars a detour of more than a couple of miles eats a two-pence saving whole.
Both carry loyalty schemes — Membership required to buy fuel and Asda Rewards (points in the app, not on fuel by default) — which shift the effective price by an amount that depends on how much you redeem rather than how much you fill. Beyond that, the fuel itself is the same specification at both — what actually differs between supermarket and branded fuel is the additive package, not the base product.
Cheapest forecourt of each right now
Lowest petrol price in each network today.
Common questions
Is Costco or Asda cheaper for petrol?
Costco is cheaper today, at £1.62 a litre against £1.69 — a difference of 6.8p, or £3.74 on a 55-litre tank. Those are medians across each network, so an individual forecourt near you can easily reverse the order.
How much would switching between Costco and Asda save in a year?
On today's difference of 6.8p a litre, a driver filling a 55-litre tank once a fortnight would save about £97 a year — £3.74 a fill. That assumes the gap holds, which it does not always: the ranking between two chains can swap within a month.
Does Costco fuel differ from Asda fuel?
Standard E10 petrol and B7 diesel are the same specification wherever you buy them — they meet the same British Standard, and are frequently refined and delivered by the same companies regardless of the sign on the forecourt. What differs is the additive package blended in at the terminal, which is where premium grades and branded formulations come in. For an ordinary car on ordinary journeys, the manufacturer's handbook is the authority on whether that is worth paying for.
Which has more forecourts, Costco or Asda?
Asda has more: 405 forecourts currently reporting a price against 22. Costco covers 9 of the twelve UK regions and Asda covers 12. Network size matters more than the headline price for most drivers — a chain that is two pence cheaper but forty minutes away is not cheaper.
How often are these prices updated?
Both chains report every price change to the government Fuel Finder scheme, which has required a report within thirty minutes of a change taking effect since February 2026. The figures here refresh throughout the day from that feed.