One excellent site to compare vehicles' gas mileage, or miles per gallon, is ConsumerReports.org. Consumer Reports recently published an article that listed over 100 cars, trucks, SUVs and minivans along with their respective mileages, ranking them and determining which vehicles from each category got the best and worst mileage.
Although ConsumerReports.org is a well-reviewed website with a myriad of different reviews, users must subscribe and pay an annual fee in order to view the full site. One website that allows users to directly compare gas mileages of different cars for free is FuelEconomy.gov. On this website, users can select up to four vehicles, specifying the vehicles' year, make, model and options, and then compare the gas mileage and other details among all four models side by side.
FuelEconomy.gov, an official site of the U.S. government, also features articles on the most fuel-efficient cars and trucks, as well as the nation's most popular cars and trucks. Users can download historical data files in Excel or PDF format that detail fuel economy data for a wide variety of vehicles, going back over 35 years. The fuel economy data in these files result from official tests that the Environmental Protection Agency performed on the vehicles.