If you are on a budget or just interested what sort of mileage you get in different environments, this is for you!
First you will need a subject, for my subject I am using our motor home, I will show you a 7 fill period (consecutive) of our driving. My topics in the subject will be: KPL (kilometers per liter), the condition of the driving, how far we drove and how much we filled up at each stop. The last step will show you the calculations to make to figure out your own fuel consumption.

Before I get started I will note a few things, we are driving a diesel, all my specs are in kilometres and litres NOT miles and gallons.

Step 2: Start of Filling

Fill one, filled up with 170 litres, we drove in a strong headwind, got 691.6km and our fuel consumption was 4.068kpl.

Step 3: Fill Two.

Fill two, filled up with 151.9 litres, we drove on bumpy roads and in warm weather, got 678.9km and our fuel consumption was 4.469kpl.

Step 4: Fill Three.

Fill three, filled up with 156.02 litres, we had flat driving, got 660.3km and our fuel consumption was 4.232kpl.

Step 5: Fill Four.

Fill four, filled up with 138.24 litres, we had mostly hwy driving and one small range to cross, got 591.6km and our fuel consumption was 4.279kpl.

Step 6: Fill Five.

Fill five, filled up with 140.03 litres, we had easy hwy driving, got 594.5km and our fuel consumption was 4.245kpl.

Step 7: Fill Six.

Fill six, filled up with 146.4 litres, we had very hilly and windy driving, got 565.5km and our fuel consumption was 3.862kpl.

Step 8: Fill Seven.

Fill seven, filled up with 140 litres, we had hilly driving and one big range to cross, got 580.9km and our fuel consumption was 4.149kpl.

Step 9: The Conclusion.

The conclusion: My hypothesis was wrong, the best consumption in our case was on bupy roads in wam weather.
A few stats: The best consumption was on fill two on the bumpy roads and in warm weather, 4.469kpl. The furthest we drove was fill one, 691.6km. The most we filled up with was fill one, 170L. The worst consumption was fill six, 3.862kpl. The shortest we drove was fill six, 565.5km. The least we filled up with was fill four, 182.4L.

Step 10: How You Can Do This.

How you can do this: first, get yourself a small book (one with 80 pages has lasted us over 4 years)
You will need a pen or a pencil (to write with!) If you are not Einstein you might want a calculator… When you have all this, drive like normal until you need to fill up, when you fill up you need the reading on the odometer and the amount of fuel you put in. If you want a fancier reading you might want to note the price of the fuel and the conditions.

01/01/2015 412666.6412666.6 hwy driving 140.03L@125.5cpl (cents per litre)

11/01/2015 413232.1 565.5km hilly and very windy driving 3.862 \$237.27 146.4L@130.1cpl…

The stuff in italics is optional

Thanks for viewing, if you cannot understand something, please comment and I will do my best to help you as best I can.

<p>Please do not try to skype the numbers, they are our odometer readings, I don't know why it does that.</p>
Thanks it realy helped me.However does this has anything to do with the speed of the vehicle.