After filling up the gas tank, reset the trip odometer. Then, on the next gas fill, take note of how many miles where driven since the last fill. Divide by the amount of gas put into the tank and that will give the vehicle's miles per gallon. For accurate results, the tank must be completely filled during both fills, and the car has to be driven to nearly empty.Continue Reading
A car's expected MPG will be different depending on the type of driving done. Most cars come with a city MPG and a highway MPG and some will provide a combined value. These values are determined by the federal Environmental Protection Agency by rigorously testing the car on a dynamometer.
City MPG is based off the stop and go conditions normally encountered while driving on the city streets, while highway MPG is based off of the continuous speed of the highway, which is a more efficient use of the engine and therefore has a higher value.
In addition, due to different road conditions and driving style, the actual MPG a driver will see varies. A higher MPG is desirable because it signifies a more efficient use of fuel, therefore reducing fueling costs to the driver and implying reduced pollution and emissions.Learn more about Motion & Mechanics