miles per gallon MPG

Miles per gallon (MPG) is a standardized measurement of a vehicle’s fuel economy, expressed as the number of miles it can travel on one gallon of gasoline (or gasoline-equivalent for diesel, hybrid, and alternative-fuel vehicles). In the United States, MPG figures are determined through laboratory testing overseen by the U.S. Environmental Protection Agency (EPA) and published on the window sticker (Monroney label) of every new car sold, as well as on the federal FuelEconomy.gov database maintained jointly by the EPA and the U.S. Department of Energy.

EPA ratings are broken into three key figures:

• City MPG: simulates stop-and-go urban driving.
• Highway MPG: reflects steadier, higher-speed cruising.
• Combined MPG: a weighted average (55% city / 45% highway) that most shoppers use for quick comparisons.

For example, a 2018 Toyota Camry LE carries an EPA-estimated 29 city / 41 highway / 34 combined MPG, while a 2018 Ford F-150 with the 5.0L V8 is rated around 17 city / 23 highway / 19 combined MPG. Electric vehicles and plug-in hybrids use a related measure called MPGe (miles per gallon equivalent), which converts electricity consumption into a comparable figure.

Why used car shoppers should care: Fuel costs are often the single largest ongoing expense of vehicle ownership after the purchase price. A difference of even 5 MPG can translate into hundreds of dollars per year at the pump. When shopping used, look up the vehicle’s original EPA rating at FuelEconomy.gov by year, make, model, and trim — ratings can vary significantly between engine and transmission options within the same nameplate.

Keep in mind that real-world MPG typically falls 10–20% below EPA estimates due to driving style, terrain, climate, tire pressure, and vehicle condition. Older vehicles may also underperform their original ratings if maintenance has been neglected (dirty air filters, worn oxygen sensors, or degraded spark plugs all hurt economy). While researching a used vehicle, it’s also wise to cross-check the National Highway Traffic Safety Administration (NHTSA) database for any open recalls, consumer complaints, and New Car Assessment Program (NCAP) crash-test ratings — fuel economy is important, but safety and reliability should weigh equally in your decision.

Sources:

• EPA / U.S. Department of Energy — FuelEconomy.gov fuel economy database
• EPA Monroney label fuel economy and environment ratings
• NHTSA — Recalls, Complaints, and Investigations database (NHTSA.gov)
• NHTSA — New Car Assessment Program (NCAP) 5-Star Safety Ratings

Reviewed by the CarCabin editorial team.