Road Trip Fuel Cost Calculator

Enter your trip distance, your vehicle's fuel efficiency, and the price per litre or gallon to see exactly what a drive will cost in fuel.

How it works

  1. Enter the trip distance and your vehicle's fuel consumption figure.
  2. Add the current fuel price per litre or gallon.
  3. The tool calculates the total fuel cost for the trip.
  4. Adjust the passenger count to split the cost per person.

The calculation

In metric mode, fuel used in litres = distance in km / 100 x fuel economy in litres per 100 km, and cost = litres x price per litre. In imperial mode, fuel used in gallons = distance in miles / miles per gallon, and cost = gallons x price per gallon. The tool does not convert between the two systems, so use the one that matches your car and fuel prices.

For example, a 450 km trip in a car that uses 6.5 litres per 100 km needs 29.25 litres, and at 1.85 per litre costs 54.11. In imperial units, 300 miles at 32 mpg needs 9.375 gallons, and at 3.60 per gallon costs 33.75.

Getting a realistic number

The result is only as good as your consumption figure. Official figures from the manufacturer are measured under test conditions and real driving usually uses more, especially with motorway speeds, a loaded car, a roof box, air conditioning, cold weather or hilly roads. The most reliable input is your own average, which you can work out by filling the tank, noting the trip meter, and dividing the litres added at the next fill by the distance driven. If you enter your fuel economy as miles per gallon, use the same type of gallon for the price: a US gallon is 3.785 litres and an imperial (UK) gallon is 4.546 litres, so an mpg figure is not comparable between the two. To convert, L/100 km = 235.2 / mpg for US gallons, or 282.5 / mpg for UK gallons.

What is not included

The tool covers fuel only. Tolls, parking, ferries, wear and tear, and insurance are not included. For a return journey, enter the total distance for both ways. To split the cost between passengers, divide the result by the number of people. If you drive an electric car, use the EV Charging Cost tool instead, which handles charging loss, tariffs and fast-charger fees.

Frequently asked questions

What if I do not know my exact fuel efficiency?

Check your vehicle's manual or a recent fill-up — miles or km driven divided by fuel used — for a rough figure. Even an estimate gets you a useful ballpark cost.

Does this account for traffic or driving style?

No — it uses your entered average efficiency figure, which already reflects your typical driving conditions if you calculated it from a real fill-up.