Fuel Cost Calculator
How much fuel a journey will use and what it will cost, from the distance, your car's economy (mpg or L/100 km) and the price at the pump, with return trips and cost per person.
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How to work out the fuel cost of a journey
- Enter the distance in miles or kilometres, and tick Return trip if you’re coming back.
- Enter your car’s fuel economy in mpg (UK or US), L/100 km or km/L.
- Enter the fuel price and how many people are sharing to see the cost each.
How it's worked out
Fuel used is the distance divided by how far the car goes on each unit of fuel (or multiplied by its L/100 km figure), and the cost is the fuel used times the price. A UK (imperial) gallon is 4.546 litres and a US gallon 3.785 litres, so the same car shows a higher mpg figure in the UK than in the US: 40 UK mpg is 33.3 US mpg, or 7.1 L/100 km. Make sure the mpg and the gallon match.
Real-world economy is usually 10–25% worse than the official figure, more on short trips, in cold weather, with roof boxes or at motorway speeds above 70 mph, so use your car's trip computer average if you can. For an electric car, use the Electricity Cost Calculator with the car's kWh per mile. Everything is calculated in your browser.
Questions about fuel costs
How much does it cost to drive 100 miles?
At 45 mpg (UK) and £1.40 a litre, about £14.14 in fuel. Enter your own car’s figures to see yours.
What is the difference between UK and US mpg?
A UK gallon is 4.546 litres and a US gallon 3.785 litres, so the same car shows a higher mpg in the UK: 40 UK mpg is 33.3 US mpg.
Why does my car use more fuel than the official figure?
Real-world economy is usually 10–25% worse, especially on short trips, in cold weather and at motorway speeds. Your trip computer’s average is more realistic.
How do I work out the cost for an electric car?
Use the electricity cost calculator with your car’s kWh per mile and your electricity price.