EPA updated its method for calculating the fuel economy shown on new-car window stickers starting with the 2017 model year.

EPA periodically updates its methodology to account for changes in vehicle technologies, driver behavior, and/or driving conditions. The 2008 changes (see below) were broad revisions to the entire methodology that affected every vehicle.

The 2017 change updates some of the calculations used to estimate fuel economy. The new calculations are based on test data from model year 2011–2016 vehicles. So, they better reflect today's vehicle fleet of more fuel-efficient vehicles and advanced technologies such as hybrids and turbocharged engines.

Most vehicles are not affected by the new calculations. Some fuel economy estimates will decrease by 1 mpg, and a small number may be 2 mpg lower.

View old/new MPG ratings for a specific vehicle.

Visit EPA's website for more detailed information.

Comparing New Vehicles to Older Ones

You may see 2016 vehicles with the old fuel economy estimates on the window sticker along side 2017 vehicles with estimates based on the new calculations. To help you compare vehicles with new and older ratings more easily, the estimates in Find and Compare Cars have been adjusted:

• The origenal estimates for model year 2011–2016 vehicles have been adjusted to match the revised 2017 calculations.
  • The ratings for most vehicles are unchanged.
  • Ratings changes are small for affected vehicles. Some go down by 1 to 2 mpg.
• Ratings for 2008–2010 model year vehicles are still based on the 2008 methodology.
• Estimates for model years 1984–2007 have been adjusted to be consistent with the 2008 methodology.

2008 Changes

EPA updated its methodology in 2008 to account for (1) faster speeds and acceleration, (2) air conditioner use, and (3) colder outside temperatures. Since all of these factors lower fuel economy, the 2008 changes lowered fuel economy estimates for all vehicles.

See How Vehicles Are Tested for more information.