How to calculate the fuel for a trip
- Pick the unit system (kilometers and liters, or miles and gallons) and, if you like, a vehicle type to load a typical fuel economy.
- Enter the trip distance and your vehicle's fuel economy (in L/100 km, km/L or mpg). Check «Round trip» if you come back the same way.
- Enter the fuel price, any tolls and how many people share the cost.
- See how much fuel you need and what the trip costs, per person and per kilometer. The average speed gives you the travel time, and the tank size gives you the range.
How fuel and cost are calculated
The math is straightforward: the liters you need are the distance multiplied by the fuel economy and divided by 100 (when the fuel economy is in liters per 100 kilometers). The fuel cost is that number of liters times the price per liter, and the total cost adds tolls and other expenses.
If your fuel economy is in km/L or mpg, the calculator converts it: 12.5 km/L equals 8 L/100 km, and 30 mpg (US gallons) equals 7.84 L/100 km. Travel time is the distance divided by the average speed.
The most accurate way to know your fuel economy is to measure it: fill the tank, write down the odometer, and at the next fill-up divide the liters added by the distance driven. The «Calculate my real fuel economy» section does it for you. Everything is calculated on your device and nothing is sent anywhere.
Things to keep in mind
- The fuel economy values in the list are typical and approximate; your vehicle's may be very different. It is best to enter your own.
- Real fuel economy changes with the load, the weather, traffic, speed and the condition of the vehicle. A highway trip usually uses less fuel than a city one.
- No maps are used and your location is not requested: you enter the distance yourself. No fuel price is assumed.
- In the imperial system the US gallon (3.785 liters) is used, not the imperial (UK) gallon.
Frequently asked questions
How do I calculate how much gas I use on a trip?
Multiply the distance by the fuel economy in liters per 100 km and divide by 100. For example, 500 km at 8 L/100 km is 40 liters.
How do I convert km/L to L/100 km?
Divide 100 by the km/L. For example, 12.5 km/L is 100 ÷ 12.5 = 8 L/100 km. The calculator does it for you when you change units.
How do I find my vehicle's real fuel economy?
Fill the tank and write down the odometer reading. At the next fill-up, divide the liters added by the distance driven and multiply by 100. The calculator has a section that does it.
Can I calculate the cost per person?
Yes. Enter how many people share the expense and the total cost, tolls included, is divided among them.
Does it work for electric or natural gas vehicles?
This version is for liquid fuels measured in liters or gallons. For an electric vehicle you can use the electricity usage calculator with your price per kWh.