Road trip fuel cost calculator
Enter your route and your car. We correct the official figure to real-world fuel economy and adjust it for road type, load, air conditioning and traffic, using factors from published studies.
Why is this calculator more accurate?
- It corrects the brochure figure to real-world fuel economy: on average 17–20% more than WLTP, according to European Commission and ICCT data.
- It works out each road type separately, and air conditioning per hour of use: it weighs a lot in town and little on the motorway.
- It gives you an estimate range instead of a falsely precise number, and cites the source of every factor.
Fuel consumption guides
Real-world vs official fuel economy (WLTP, NEDC and EPA)
Cars use on average 17–20% more fuel than their WLTP rating and 39% more than NEDC. EU and ICCT data, and how to correct for it when costing a trip.
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Petrol or diesel: which is cheaper for your annual mileage?
A diesel uses 17–26% less fuel but usually costs more to buy. How many kilometres a year it takes to win back the difference, at today’s fuel prices.
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How to work out your car’s real mpg
How to work out your car’s real mpg with the brim-to-brim method, UK and US gallons, and why it won’t match your trip computer or the official figure.
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Air conditioning or windows down? Which uses more fuel
Air conditioning uses a near-constant amount per hour; open windows cost more the faster you go. ORNL and EMPA data for town, country roads and motorways.
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Roof boxes, roof racks and luggage: how much more fuel
A roof box raises fuel use by 10–25% on the motorway, and 100 kg of load by about 2–3%. Data from the US DOE, ADAC and ORNL, and how to reduce the impact.
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How to cut your commuting fuel costs
The drive to work is often the least efficient trip: town traffic, queues and air conditioning. What actually saves fuel, with data and a worked example.
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Calculators for every trip
MPG calculator
Work out your car’s real mpg or L/100 km from the fuel you put in and the distance you drove.
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Commuting fuel cost
Work out the daily, monthly and yearly fuel cost of driving to work, and each person’s share if you car-share.
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Campervan and motorhome fuel cost
Work out what your route will cost in a campervan or motorhome, with adjustments made for these vehicles.
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