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Diesel costs 29.2p a litre more than petrol at the same pump

Diesel B7 averages 197.2p a litre across Britain and unleaded E10 averages 168.0p. The more useful comparison is at the 7,295 forecourts that sell both, where the difference between the two pumps on the same forecourt is 29.2p a litre, or £16.05 on a 55-litre tank. The duty on the two fuels is identical, so none of this gap is tax.

The gap is not tax

Fuel duty is the same rate on petrol and diesel, and VAT is the same percentage. Every penny of the difference happens before tax, in what the fuel costs to buy and refine and in what the retailer takes. Our breakdown of a litre shows where each part of the price goes.

It depends where you fill up

The gap is not the same everywhere, and the difference between kinds of forecourt is real.

Where the two pumps are closest

At these forecourts diesel and unleaded are nearly the same price, which is as close as the market gets to treating them alike.

And where they are furthest apart

Diesel is cheaper than petrol at 5 forecourts

Most drivers take it as given that diesel costs more. At 5 of the 7,295 forecourts selling both, it does not. That is 0.1% of them, and it is a reminder that the national average describes the market rather than your street.

The dearest places for diesel

How this is measured

Unleaded E10 and diesel B7, the two grades most drivers buy. The headline gap uses only the 7,295 forecourts reporting both, so it compares two pumps on one forecourt rather than two different sets of sites. Forecourts whose prices have not moved in 14 days are excluded, and so are prices more than 25% from the national median for their grade. Data as at 2026-11-10.

Source: the government Fuel Finder scheme, run by the Department for Energy Security and Net Zero, which retailers are legally required to submit to. Figures recalculated on every build.