Measuring Fuel Consumption

The current fuel consumption test is a standard laboratory assessment designed to exclude the myriad of variables that a vehicle is subjected to in everyday driving. 

These variables include:

  • road, traffic, and weather conditions
  • driving style
  • vehicle speed, load, and condition 
The intent is to provide figures that will allow comparison of one vehicle to another, but as we know these figures aren’t representative of the fuel consumption a vehicle might achieve under actual operating conditions. 

For motorists, the only readily available fuel consumption test method involves actual on-road driving and calculation of fuel consumption based on the distance travelled and the volume of fuel used. 

The following formula is used to calculate fuel consumption in litres / 100kms, the most commonly used measure of fuel consumption.

(Litres used X 100) ÷ km travelled = Litres per 100km.

Example a car uses 65 litres to travel 500km

(65 X 100) ÷ 500 = 13

It's important to note when comparing on-road fuel consumption figures that differences in road, weather and vehicle conditions can alter fuel consumption figures considerably, even for an apparently similar trip.