How much is a gallon of petrol in the UK?

The short answer

On our latest figures, a gallon of unleaded petrol (E10) costs £7.81, at the UK average of 171.7p a litre across 6,893 forecourts. A gallon of diesel (B7) costs £9.02, at 198.4p a litre. To get that, multiply the price of a litre by 4.54609, the number of litres in a UK gallon^[1]: 171.7p × 4.54609 = £7.81.

The lowest unleaded price in our data is 153.9p a litre, or £7.00 a gallon. The highest is 209.0p, or £9.50 a gallon.

These UK averages come from 6,893 forecourts with an unleaded price and 6,341 with a diesel price in our price data. We update it every 15 minutes. See how we work them out.

Most of the prices behind these averages are more than 3 days old.

Updated 6:47am on 2 November.

How many litres are in a gallon?

A UK gallon, also called an imperial gallon, is exactly 4.54609 litres^[1]. That is about 4.5 litres.

So 4 litres is less than a gallon, at 0.88 of a gallon. 5 litres is a little more than a gallon, at 1.10 gallons.

Prices are the UK averages at the top of the page, from our price data. Most of the prices behind the unleaded average are more than 3 days old.

A UK gallon against a US gallon

A US gallon is smaller, at about 3.785 litres^[2]. So a UK gallon holds about 20% more. A US mpg figure uses the smaller gallon, so 30 US mpg is about 36 UK mpg.

At the latest unleaded average of 171.7p a litre, a US gallon of petrol would cost £6.50 here. A UK gallon costs £7.81.

Prices are the UK averages at the top of the page, from our price data. Most of the prices behind the unleaded average are more than 3 days old.

Why pumps show litres but cars use mpg

Petrol and diesel have been sold by the litre in the UK since 1 October 1995. That is when the gallon stopped being a unit for trade^[3].

A seller can still show a price for a gallon, but only as an extra beside the price for a litre^[1].

Miles per gallon on this site, and in our fuel cost calculator, means miles per UK gallon.

An average petrol car does 44.6 mpg on the figures we use. At the latest unleaded average, a mile costs 17.5p in fuel.

Prices are the UK averages at the top of the page, from our price data. Most of the prices behind the unleaded average are more than 3 days old.

Work out what a journey costs with our fuel cost calculator.

The price of a gallon in each region

A gallon of petrol is cheapest in Northern Ireland, at £7.46, and dearest in the South East, at £7.89. Diesel runs from £8.68 a gallon in Northern Ireland to £9.10 in the South East.

Regional averages from our price data, across every forecourt in each region. A region is listed once at least 100 of its forecourts have a petrol price and at least as many have a diesel price.

Figures marked † are mostly from prices over 3 days old.

Regional averages updated 6:47am on 2 November.

Supermarkets and the big brands

On our latest figures, supermarket petrol averages 170.0p a litre, or £7.73 a gallon. At the major brands it averages 171.8p, or £7.81 a gallon. That is 8p a gallon less at the supermarkets.

Supermarket diesel averages 195.9p a litre, or £8.91 a gallon. At the major brands it averages 198.8p, or £9.04 a gallon. That is 13p a gallon less at the supermarkets.

These averages come from 1,409 supermarket and 4,601 major-brand forecourts with a petrol price in our price data, not counting motorway services.

Most of the prices behind these averages are more than 3 days old.

Supermarket or branded fuel: is there a difference?

For prices at motorway services, see our motorway pages.

The UK average price of a gallon of petrol and diesel each day since 7 February 2026, in pounds.

• On 1 November 2026, a gallon of petrol averaged £7.81 and diesel £9.02.
• Petrol peaked at £7.95 a gallon (174.9p a litre) on 5 October 2026. It was lowest at £6.01 (132.1p a litre) on 10 February 2026.
• Diesel peaked at £9.10 a gallon (200.1p a litre) on 5 October 2026. It was lowest at £6.42 (141.2p a litre) on 9 February 2026.

Daily figures from 7 February 2026 to 1 November 2026.

Daily UK averages from our price data: each forecourt's price in effect at the end of the day.

For each fuel's daily average a litre, see our UK fuel price index. Each month's figures are in reports such as UK fuel prices in September 2026.

How much of a gallon is tax

Fuel duty is 52.95p a litre on petrol and diesel^[4]. On a gallon that is £2.41. VAT at 20% is then charged on the fuel and the duty together^[4]. So VAT is 16.7% of the pump price.

On a gallon of unleaded at £7.81, VAT is £1.30. With duty, tax comes to £3.71, or 48% of the price.

On a gallon of diesel at £9.02, VAT is £1.50. With duty, tax comes to £3.91, or 43% of the price.

Prices are the UK averages at the top of the page, from our price data. Most of the prices behind these averages are more than 3 days old.

How fuel duty works, and how it has changed.

Common questions about the price of a gallon

Sources and method

1. legislation.gov.uk: Weights and Measures Act 1985, Schedule 1, checked 15 October 2026.
2. NIST: Guide for the Use of the International System of Units (SP 811), Appendix B.9, Factors for units listed by kind of quantity, checked 25 October 2026.
3. legislation.gov.uk: The Units of Measurement Regulations 1994, checked 25 October 2026.
4. GOV.UK: Tax on shopping and services, Fuel Duty, checked 13 October 2026.

Our figures: each UK average is over every forecourt's latest price reported in the last 30 days, leaving out prices far from what the rest of the UK charges. The supermarket and major-brand figures leave out motorway services. Every gallon is the price of a litre, as printed, times 4.54609. How we work out the figures