The moment when you get the figures for the calculation is when you fill up a second time.

So you fill-up the first time completely then you use your car for maybe one week maybe more until your fuel tank is at about one-quarter of capacity.

By that time you’re going to fill up a second time and again it’s always filling up completely. What do you do in this second fillup is to take note of the litres that you filled up with (you can get that in the proof of payment) and take note of the kilometers the car traveled between the two fillups.

Let’s recap how to do it:

- Fill up your tank completely;
- Reset the trip odometer before you start your car to leave the gas station;
- Use your car like you normally would;
- When your tank is running low, go to the gas station for the second fillup;
- Before resetting the trip odometer take note of the distance you traveled between the two fill-ups (You can also take a photo of the odometer during each fillup and later calculate the difference);
- Take note of the litres you’ve just filled up;
- Calculate your fuel economy with the right formula.

What formula is that?

It’s the one I already mentioned in another article explaining how to calculate fuel consumption.

### How to calculate combined fuel economy in Litres per 100Km

You get the liters and you divide it by the kms you’ve driven and then you multiply it by 100.

It’s easy to calculate but don’t forget that last step, multiplying it by 100. Otherwise, you will get litres per km, not litres per 100 kms.

So this is the formula –> ^{Liters consumed}⁄_{Kms traveled }x 100

Example: Imagine I traveled 650 kms while consuming 75 liters.

^{75 liters}⁄_{650 kms }x100=11,54 l/100 kms

As an example, 6 l/100 kms is more efficient than 10 l/100 kms. The lower the figure, the more efficient you are.

Your goal is to get that figure reducing over time.

## Tools to keep record of your fuel economy

As I’ve told in another video you can get those figures easily with many tools available.

These are just a few suggestions:

- Spritmonitor (Web, Android and iOS):
- Fuelio (Android)
- Drivvo (Android and iOS)
- Fuel Tracker and Gas Mileage log (iOS):

Whatever tool you use is fine.

The important part is what you do with it. Keep a record of your fuel economy on each fill-up to improve results.

You have to turn fuel economy into a habit. If you keep track of your fuel economy it will drastically increase the chances of you improving your fuel efficiency.