Road trip cost calculator
This tool works out what a car journey costs in fuel or charging, then splits it between passengers. A 200-mile trip each way at 45 mpg and 140p a litre comes to an estimated £56.57, or £14.14 each split 4 ways. There is no statutory rate behind this figure, only the distance, efficiency and price entered.
How do I work out fuel cost for a trip?
For a petrol or diesel car the tool turns MPG into litres. It divides the distance by the MPG entered to get gallons, converts each gallon to 4.546 litres, then multiplies by the pump price. For an electric car it divides the distance by miles per kWh to get the energy used, then multiplies by the price per kWh. Ticking return trip doubles the distance used in the sum.
The split is the useful part for shared journeys. The total is divided by the number of people in the car, so four people sharing pay a quarter each. That makes an EV on cheap home charging strikingly cheap per head, and it settles who owes what without argument.
What would an example trip cost?
A 200-mile trip each way, so an estimated 400 miles there and back, in a car doing 45 mpg at 140p a litre uses an estimated 40 litres and costs an estimated £56.57. Split 4 ways that is an estimated £14.14 each. The same trip in an electric car on a cheap home tariff would usually cost only a few pounds in total.
Common questions
How do I work out fuel cost for a trip?
Divide the distance by your MPG to get gallons, convert to litres, then multiply by the price per litre. A 400-mile round trip at 45 mpg uses about 40 litres, so near £56 at £1.40 a litre. This tool does the conversion for you, including the return leg.
How is an electric car trip costed?
For an EV the tool divides the distance by your efficiency in miles per kWh to get the energy used, then multiplies by your price per kWh. The same trip is usually far cheaper on cheap home charging than on petrol, and the split per person makes lift-sharing easy to settle.
Does this include the return journey?
You can tick return trip and the tool doubles the distance. Leave it unticked for a one-way cost. Either way the split per person divides the total by however many are travelling.
Why split the cost per person?
Sharing a car is one of the cheapest ways to travel. Splitting the fuel or charging cost between everyone in the car shows the real cost each, which helps when settling up fairly after a trip.
What would an example trip cost?
A 200-mile trip each way, 400 miles there and back, in a car doing 45 mpg at 140p a litre uses an estimated 40 litres and costs an estimated £56.57. Split 4 ways that comes to an estimated £14.14 each, which is the figure worth comparing against an equivalent electric car on a home tariff.
Sources & Rate Verification
Rates verified against official statutory guidance on 6 September 2026.