Why is diesel more expensive than petrol?

Today the average UK forecourt charges – a litre for diesel and – for petrol. That is a gap of – a litre. For most of the 2000s the two prices were close, and diesel was sometimes cheaper. The gap opened up in 2022 and has stayed wide since.

The tax is the same on both

Fuel duty is 53.0p a litre on both petrol and diesel. VAT is 20% on both. So the tax is not the reason. The difference comes from what the fuel itself costs before it reaches the forecourt.

Europe does not make enough diesel

Petrol and diesel both come from crude oil, but a refinery cannot simply choose to make more diesel. Cars, lorries, trains, farms and generators in Europe burn more diesel than European refineries can make. The extra used to be imported, and a lot of it came from Russia. When Russian diesel was banned in 2022 and 2023, the price of diesel on the world market jumped. It has carried a premium ever since.

Winter pushes it higher

Diesel is very similar to heating oil and jet fuel. All three come from the same part of the barrel. Every winter, demand for heating oil goes up across the northern half of the world, and that pulls diesel prices up with it. Petrol demand peaks in summer instead. So the diesel gap tends to grow from October and shrink again in spring.

Retailers price diesel differently

In 2023 the Competition and Markets Authority (CMA) found that supermarkets had raised their profit margin on diesel by more than on petrol. It still tracks the two fuels separately every month. Supermarkets sell most of the country's petrol and keep the price keen to bring in shoppers. Diesel buyers are more often businesses paying with fuel cards, and they tend to shop around less.

What you can do

Shop around. The gap between the cheapest and most expensive diesel forecourt in a town is usually wider than for petrol. Across the country today, diesel ranges from – to –. See diesel prices by region, town and brand, or set up a diesel price-drop alert for your postcode.