What should I know about miles per gallon?

What does miles per gallon mean?

Miles per gallon (mpg) refers to the number of miles you travel per gallon of fuel your vehicle burns. For example, if you travel 300 miles and burn 10 gallons of gas, your car gets 30 miles per gallon. Your vehicle's engine size generally has the greatest impact on your car's mpg, but there are ways to improve the number of miles you get per gallon. Speeding and frequent acceleration can waste up to 33 percent more gas than driving the speed limit and using the cruise control. Proper maintenance is also essential -- keeping the tires balanced and properly inflated and your air filter clean can improve your car's fuel efficiency.

FuelEconomy.gov is a government Web site maintained by the U.S. Department of Energy and Environmental Protection Agency that ranks the most fuel-efficient cars, from two-seaters to station wagons, showing the average overall highway mpg to be about 31.

The Best Miles Per Gallon Vehicles

Increased environmental awareness has encouraged vehicle manufacturers to develop more fuel-efficient cars, giving the energy-conscious consumer more options than ever for environmentally friendly driving. Popular versions of higher-mpg cars include hybrids, which combine a gas engine with an electric motor to use less fuel, and diesel vehicles, which are estimated to be between 30 to 35 percent more fuel efficient than gasoline engines of the same size. Popular fuel-efficient cars include the 2008 Honda Civic Hybrid and the 2008 Toyota Prius. Both get an estimated 45 mpg on the highway -- roughly 10 miles more per gallon than each manufacturer's non-hybrid version of a similar engine size. FuelEconomy.gov lets users compare the miles per gallon of popular fuel-efficient makes and models and find the best and worst cars for fuel efficiency.

Calculating Miles Per Gallon

Calculating your car's miles per gallon is simple, but it requires a bit of record-keeping on your part. One way is to record the odometer mileage each time you stop for gas as well as how many gallons were required to fill your tank. Next, divide the number of miles you traveled between gas station stops by the number of gallons of gasoline your vehicle burned. The result will be your average miles per gallon. For example, if you traveled 300 miles and burned 10 gallons of gas, your car averages 30 miles per gallon. For additional help with the process, visit FuelEconomy.gov, which walks you through two methods of calculating your miles per gallon, or Edmunds.com, which provides a helpful "green car guide."