All The CalcsFree UK calculators for work, home projects and driving

For UK drivers. Distances in miles, fuel in litres and imperial gallons.

Fuel cost calculator

Work out what a journey costs in petrol or diesel, using UK miles per gallon and pence per litre.

Fuel cost

Rates and rules used: 1 UK gallon = 4.54609 litres; 1 US gallon = 3.785411784 litres. Fuel price is whatever you enter. Sources: Weights and Measures Act 1985 (imperial gallon). Checked 16th September 2026. Mileage rates are reviewed each tax year.

How it works

UK miles per gallon use the imperial gallon, which is 4.546 litres. The calculator divides the distance by your mpg to get gallons, converts to litres and multiplies by the pump price. Use your car's real-world mpg rather than the brochure figure for a more realistic answer.

Common questions

Where can I find current fuel prices?

Pump prices change often. Use the price shown at your local forecourt or a fuel price comparison service.

More calculators and guides

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These calculators give estimates. Fuel prices, energy tariffs and real-world economy vary. This is general information, not tax or financial advice. Mileage rates checked against GOV.UK on 16th September 2026.