What's the difference between US MPG and UK MPG?

The size of the gallon. UK MPG uses the 4.546-litre imperial gallon; US MPG uses the 3.785-litre US gallon. 30 MPG (US) is about 36 MPG (UK).

How do I split fuel costs between passengers?

Enter the number of people in the 'Split the cost between' box — the calculator shows the cost per person alongside the total. Tick round trip if you're coming back.

Fuel Cost Calculator

Work out how much fuel a trip needs and what it will cost — in kilometres and litres, US miles and gallons, or UK miles with MPG and prices per litre.

Trip distance

Distance unit

Fuel efficiency

Efficiency unit

Fuel price

Price is per

Round trip (double the distance)

Split the cost between (people)

Fuel needed = distance × consumption. US and UK MPG differ: a UK (imperial) gallon is 4.546 L and a US gallon is 3.785 L, so the same car shows a higher MPG figure in the UK. Real consumption varies with speed, traffic, load, weather and driving style, so treat this as an estimate.

€29.25

Total fuel cost

16.25

Fuel needed (litres)

€0.12

Cost per km

Based on 250 km at €1.8 per litre.

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How to use fuel cost calculator

1Pick a unit preset — metric, US or UK — or set each unit yourself.
2Enter the trip distance and your vehicle's fuel economy.
3Enter the fuel price and whether it's per litre or per gallon.
4Tick round trip to double the distance and, if you're sharing, enter how many people split the cost.

About this tool

Fuel needed = distance × consumption. Everything is converted to kilometres and litres first, so you can mix units freely — a UK driver can enter miles and MPG with a price per litre. A 300-mile trip at 30 MPG (US) needs 10 US gallons, which costs $35 at $3.50 a gallon.

US and UK MPG are not the same: a US gallon is 3.785 litres and an imperial (UK) gallon is 4.546 litres. The same car might be rated 36 MPG in the UK and 30 MPG in the US. Choose the right one or the cost will be about 20% off.

Real-world economy depends on speed, traffic, terrain, weather, load, tyre pressure and driving style, and official figures are often optimistic. Use your own measured economy (the MPG Calculator can work it out) for the most realistic estimate. Tolls, parking and wear aren't included.

Frequently asked questions

Divide the distance by your fuel economy to get the fuel needed (or multiply by L/100 km and divide by 100), then multiply by the price per litre or gallon.

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