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.
Read the guide →
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.
Read the guide →
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.
Read the guide →