Do you want to? If so there is a free Website that will help you do exactly that. My Mile Marker is a great site that will keep track of your fuel use and give you a complete record of your fuel usage and mpg. Naturally some people would say that this could easily be done by making a note of your mileage at the beginning and end of the month, add up all of your fuel receipts and then divide on by the other. But this is not hi tech; it does not involve computers and lovely graphics.
With My Mile Marker you make a not of the mileage of your car when you visit the service station and make a not of the fuel added, plus the price per gallon, you can do this by making notes an adding to your PC when you get home, laptop if you have it with you or you can even send off an SMS to the system via Twitter.
On the site you get some glossy charts and figures, that will show to you exactly how much fuel you are using, what your MPG is and how much each mile is costing you.
This is a useful tool for company vehicles to keep track of the costs of running different types of vehicles in different areas, with fuel and terrain being different all over the country; the results would be very interesting to see. We find out the most expensive and the cheapest places to drive in. I wonder where they are?
Source [Auto Blog]