Gas Mileage Calculator
Measure fuel economy from distance traveled and fuel consumed.
Your result
EVERYDAYEnter your values and select calculate.
On this page How it works & practical examples
How to use the Gas Mileage Calculator
Use a distance and fuel quantity measured over the same interval. A common approach is to compare the distance between similar full-tank fills with the fuel required to refill, while allowing for filling and odometer uncertainty. The calculator reports both a consumption figure and an economy figure, so you can compare metric and US labels without reversing their meaning.
The calculation
Worked example
Driving 500 km while consuming 35 liters gives 7 L/100 km. This corresponds to approximately 33.6021 miles per US gallon.
Assumptions and limits
Distance and fuel must both be positive. This tool uses US gallons, not imperial gallons. Short measurements can be distorted by differences in tank filling, terrain, traffic and driving conditions. It does not correct an odometer or estimate fuel left in a tank. Future-trip cost is better handled by the Fuel Cost Calculator.
Common questions
Does a lower L/100 km mean better economy?
Yes. It means less fuel per distance. For mpg, higher is better because it means more distance per fuel unit.
Can I enter imperial gallons?
No. Convert them to liters or US gallons first. The US gallon used here is 3.785411784 liters.