Calculate your cars fuel economy


If you own and drive a car, it's useful to know how much fuel your car consumes so that you can take the necessary steps to reduce excessive fuel consumption. This article will show you how to calculate your car's fuel economy so that you can compare your fuel economy over time.

How do I calculate my car's fuel economy?

Calculating your car's fuel consumption is easy if you know the distance travelled and the amount of fuel used to travel that distance. Here's what you need to do,

  • Fill up your tank with fuel
  • Record your current mileage as displayed on your odometer. If your car has a trip odometer, reset it to zero.
  • Drive your car normally until you need to fill up again
  • When the fuel tank is empty, fill it up
  • Record how much fuel you used
  • Use your trip odometer to see how many kilometres you have travelled since your last fill up. If you don't have a trip odometer, record the latest odometer reading and subtract the first odometer reading to determine how far you have driven,
  • To work out how many kilometres your car drives on one litre of fuel simply divide the total distance travelled by the total litres of fuel used. Example: 400 km / 42 litres = 9.5 km's per litre.
  • To find what your car's fuel economy is (Metric System), multiply the amount of fuel used by 100 and divide that by the total kilometres driven. Example: 42 litres x 100 / 400 = 10.5 litres / 100km.

Tip: Repeat this process randomly to compare your fuel economy over time. If your fuel economy increases drastically, it may be an indication of a mechanical fault that may need the attention of a professional. There are many factors that may influence your car's fuel economy both positively and negatively. Some of these factors include driving techniques, road conditions and your car's overall mechanical condition. Read Fuel Efficient Driving Techniques if you want to know how you can improve your car's fuel economy.


Knowing how much fuel you car consumes and taking the necessary steps to mitigate excessive fuel consumption can save you money in the long run. Check your fuel economy on a regular basis and take the necessary action if your fuel economy is unusually high.