Calculating fuel costs for a trip: formula and examples

The basic formula

• Liters needed = distance in km ÷ kilometers per liter (or: distance × consumption per 100 km ÷ 100).
• Fuel costs = liters needed × liter price.
• Calculation example (fictional): 300 km with a car that consumes 6 liters per 100 km costs 18 liters. At €1.90 per liter, that is €34.20.

Knowing the real consumption

A car's official consumption (WLTP) is often lower in practice than what you actually consume. Speed, weather, luggage, and driving style make a big difference. The most reliable is your own average: fill up, note the mileage, drive, fill up again, and divide the kilometers driven by the number of liters refueled.

In Tankmapper, you can fill in your consumption yourself or, for a Dutch license plate, use public vehicle data as a starting point.

Including detours

Anyone who deviates from the route for a cheaper station consumes extra fuel. Those costs belong to the trip. Tankmapper calculates the distance from your route to the station and back with real road distances, not as the crow flies, and subtracts the extra fuel from the saving.

Out and back, and multiple stops

On long trips, you sometimes need more than one refueling stop. Then it's not just important where you refuel, but also how much. Sometimes it's smarter to only partially refuel in an expensive country and the rest in a cheaper country further along. Tankmapper therefore plans all stops, with a safe reserve, and shows the costs per stop.

Sharing costs

Are you driving with others? Then divide the total fuel costs by the number of occupants. With the share button in Tankmapper, you send a short link with the route, the stops, and the costs, so everyone has the same overview.