litre per 100 kilometres

Unit whose name includes an SI unit and a non-SI unit accepted for use with SI

Name	Symbol	Quantity	SI units
litre per 100 kilometres	L/100 km	fuel efficiency	m³/10⁸ m
The litre per 100 kilometres, symbol L/100 km, is a non-SI unit of fuel efficiency, accepted for use with the SI. One litre per 100 kilometres is equal to a fuel comsumption rate of 1 dm³ per 100 kilometres.
Definition			c² Δν_Cs^-2
$1 \mspace{4mu} \text{L/100 km} \mspace{6mu} = \dfrac{(9 \mspace{4mu} 192 \mspace{4mu} 631 \mspace{4mu} 770)^2}{(10^8)(299 \mspace{4mu} 792 \mspace{4mu} 458)^2} \mspace{6mu} \dfrac{c^2}{{\Delta \nu _{Cs}}^2}\\ \\ \\ 1 \mspace{4mu} \text{L/100 km} \mspace{6mu} \approx 9.402 \mspace{4mu} 391 \mspace{4mu} 313 \mspace{4mu} 904 \mspace{4mu} 046 \mspace{4mu} 861 \times10^{-6} \mspace{6mu} c^2 \mspace{4mu} {\Delta \nu _{Cs}}^{-2}$

Fuel efficiency

The fuel efficiency of a vehicle relates distance travelled and the amount of fuel consumed.

A vehicle that consumes one litre of fuel to travel a distance of 100 kilometres has a fuel consumption rate of one litre per 100 kilometres.

For a vehicle travelling at an average speed of 100 km/h, the fuel consumption rate, in litres per hour, will be equal to the fuel comsumption in litres per 100 kilometres.