About these units
miles per gallon (US) (mpg)
Miles per gallon (mpg) is the distance in miles per US gallon. Higher is better. UK mpg uses the larger imperial gallon, so its figures are about 20% higher.
liter per 100 km (L/100 km)
Liters per 100 km measures how much fuel it takes to drive 100 km. Lower is better. It is the standard in Europe, China and Australia.