Journey planning
Trip Cost Calculator
UK average today: 168.9p — edit to use your local price.
Car Trip Cost Calculator UK
Work out the petrol or diesel cost of a commute, day out or road trip. Fuel used in litres = (distance in miles ÷ UK MPG) × 4.54609. Journey cost = litres × price in pence per litre ÷ 100. For a return journey, we double the distance; for a shared trip, we divide the total by the number of people travelling.
Car-type MPG figures are estimates. Use your measured fuel economy for a more useful result. Prices come from the UK Government Fuel Finder scheme and are refreshed regularly; stations report when a price changes and the pump price is final.
Frequently asked questions
How does number-plate lookup estimate MPG?
DVLA supplies vehicle details and, when available, an official CO2 figure—not MPG. We estimate litres per 100km as CO2 divided by 23.2 for petrol or 26.5 for diesel, then UK MPG as 282.481 divided by that result. This is an estimate, not measured fuel economy: you can edit it. We never include your number plate in share links. Electric vehicles are not supported by this petrol/diesel calculator.
How do I calculate fuel cost for a journey?
Divide the journey distance in miles by your car’s UK MPG, multiply by 4.54609 to get litres, then multiply by the fuel price in pounds per litre. Tick return journey if your distance is one way.
How do I find my car’s MPG?
Use the average MPG on your trip computer or calculate it from miles driven and fuel used. Manufacturer figures and our car-type presets are estimates; real MPG varies with traffic, speed and driving style.
Is diesel cheaper per mile than petrol?
It depends on both pump price and fuel economy. Diesel can cost more per litre but use fewer litres for the same distance. Compare each car’s actual MPG and the relevant fuel price to see which is cheaper per mile.
Does this calculator use UK or US gallons?
It uses UK imperial gallons: one gallon is 4.54609 litres. US MPG figures are not directly comparable, so enter UK MPG.
How current are the suggested fuel prices?
UK averages use each qualifying station’s latest reported price within the last 14 days. We refresh our Fuel Finder data regularly, about every 15 minutes; retailers can take up to 30 minutes to report changes. The pump price is final.