Fuel consumption need-to-knows

Today, most vehicles are fitted with calculators that can estimate what your fuel consumption is, how far you can still travel with the fuel in your car and more. We all know less is more when it comes to fuel consumption (less fuel per kilometre), but how do you calculate it to see when you’re in the less or the more? We’re answering some of your questions.

What is it?

Fuel consumption is defined as “the rate at which an engine uses fuel, [and is] expressed in units such as miles per gallon or litres per kilometre.”

How to calculate it?

  1. When you stop to fill up your car, write down how many litres of fuel you’re buying.
  2. Press the reset button on your odometer (it won’t reset the overall total) or take note of what your vehicle’s mileage is.
  3. Before you fill up with petrol again, write down the distance you drove. If you reset your odometer, you can use that number or subtract the new mileage from what you previously written down.
  4. Remember, be careful when your tank is nearing empty, so you don’t get stuck without petrol.
  5. Divide the kilometres driven by the amount of fuel you bought in step one.
  6. You’ll need to repeat this a few times to get an average.

If you’re unsure about your math skills, you can use CarZar’s calculator.

Let’s use a light vehicle to explain the calculations. The manufacturer states that with a tank capacity of 37 litres you can drive about 726 kilometres with the vehicle. Divide 726 by 37, and you’ll get 19.62 km/l which equals 5.097 l/100 km. However, in actuality, this vehicle’s average fuel consumption is 5.8 l/100 km, which means you can travel 17.24 kilometres on one litre of fuel. So, if you multiply 17.24 (amount of kilometres per litre) by 37 (amount of fuel the tank takes), you get 637.88 kilometres – this is how far you can drive on one tank in real life. 

Why is there a difference between actual and manufacturers’ measurements?

When vehicle manufacturing companies test fuel consumption for their vehicles, they do so in the best possible conditions. The vehicles are driven at a slower speed and in a controlled and optimal environment. Also, the vehicles aren’t tested while carrying passengers and luggage. All these conditions contribute to ideal fuel consumption measurements.

Does fuel consumption stay static?

There are plenty of factors that influence your fuel consumption, and you have a lot of control over it. For instance, stick to the speed limit and, as we’re living in South Africa and heat is a problem, use your air con sensibly. If you’d like more tips on how to decrease your fuel consumption, here are tried-and-tested tips. Best of all, if you’re a Safe and Sound Early Warning subscriber, you can monitor your driving behaviour via our Safe and Sound app. Visit www.netstar.co.za or call 0860 12 24 36 to find out more about our Safe and Sound options.


Information sources: Avis Fleet, Auto Trader, Collins Dictionary