Kilometers per liter (km/L) is the standard fuel efficiency metric used in most countries outside the US and UK, measuring how far a vehicle travels on one liter of fuel. A typical compact car achieves 12–18 km/L, while hybrids can exceed 25 km/L. One km/L equals approximately 2.352 miles per US gallon.

Miles per gallon US (mpg) measures how many miles a vehicle can travel on one US gallon (3.785 liters) of fuel, the standard efficiency metric in the United States. US EPA fuel economy ratings display city and highway mpg figures for every new vehicle. One US mpg equals approximately 0.425 km/L or about 23.52 L/100km.