How it works
Convert vehicle fuel economy between US miles per gallon, UK (imperial) miles per gallon, liters per 100 kilometers and kilometers per liter.
Miles per gallon and km/L measure distance per unit of fuel, so higher is better. Liters per 100 km measures fuel per unit of distance, so lower is better, and converting between the two families is a reciprocal, not a simple multiplication.
UK mpg figures look about 20% higher than US mpg for the same car because the imperial gallon (4.54609 L) is larger than the US gallon (3.785411784 L).
Formula
L/100 km = 235.215 ÷ mpg (US) = 282.481 ÷ mpg (UK); km/L = 100 ÷ (L/100 km)
Questions people ask
How do I convert mpg to L/100 km?
Divide 235.215 by the US mpg figure. For example, 30 mpg (US) is about 7.84 L/100 km. For UK mpg, divide 282.481 by the mpg value.
Why is US mpg lower than UK mpg for the same car?
A US gallon is about 83% of an imperial gallon, so a car travels fewer miles on it. 30 mpg (US) equals about 36 mpg (UK).
Why is L/100 km considered more useful?
Fuel used scales directly with L/100 km, so savings are easy to compare. Going from 10 to 20 mpg saves far more fuel than going from 30 to 40 mpg, which mpg figures hide.