Gas Mileage Calculator
Calculate your vehicle's real-world fuel efficiency.
Fuel Efficiency Calculator
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MPG vs. L/100km
Fuel efficiency is expressed differently around the world: the US and UK commonly use miles per gallon (MPG), where a higher number means better efficiency, while most of the rest of the world uses liters per 100 km, where a lower number means better efficiency. This calculator converts your real-world trip data into all the common formats at once.
Frequently Asked Questions
Why does a lower L/100km number mean better efficiency, while a higher MPG is better?
They measure different things: MPG measures distance per unit of fuel (more is better), while L/100km measures fuel used per fixed distance (less is better). Both describe the same underlying efficiency, just inverted.
US gallons or UK (imperial) gallons?
This calculator uses US gallons (3.785 liters). UK imperial gallons are larger (4.546 liters), if you need imperial MPG, convert your gallon figure first.
How can I get an accurate fuel efficiency reading?
Fill your tank completely, reset your trip odometer, drive normally until you need to refuel, then fill up again and note exactly how much fuel it took to refill, that's your fuel used for the distance shown on the odometer.