Free calculator
Trip cost calculator
Work out the fuel for a longer trip and split it fairly between the people in the car.
Prices prefilled from the official Fuel Finder data, updated 28 August 2026. Change any box and the answer updates as you type.
Splitting fuel fairly
Fuel is the one road trip cost that is easy to share precisely, because it depends only on the distance, the car and the price. Enter the round trip miles, the car's real world mpg and the price you expect to pay, then the number of people, and the calculator gives the total and the fair share each. Remember to count the driver as one of the people.
If the trip includes motorway driving, allow for the fact that motorway services charge well above the forecourts a few miles off the junction. Our motorway penalty calculator shows how much extra a tank costs there, and filling up before you join the motorway is one of the easiest savings on a long trip.
Making it cheaper
A heavy load and a roof box both push consumption up on a long run, so pack sensibly and take the box off when you are back. For the biggest saving, plan where you fill up. The price finder ranks every forecourt within five miles of any postcode, so you can pick a cheap stop near your destination rather than the first services you see.
Common questions
How do I split fuel costs on a road trip?
Work out the total fuel cost from the distance, mpg and price per litre, then divide by the number of people in the car, including the driver. This calculator does both for you.
Should the driver pay a share of the fuel?
Usually yes, since the driver is making the trip too. Some groups let the driver off a share to reflect wear on their car and the effort of driving, which is a fair alternative if everyone agrees.
Does motorway driving cost more?
Not in fuel per mile at a steady speed, but motorway services charge far more per litre than ordinary forecourts, so filling up there adds a lot to a trip. Fill up before you join the motorway where you can.