As the world transitions away from gasoline-powered cars and into the world of electric vehicles, some of the terminology can be confusing. As electric vehicles and plug-in hybrid vehicles (PHEV) become more prevalent, the language is necessary to understand. So, what does MPG-e mean, and why is it important?
What Is MPG-e?
MPG-e stands for miles per gallon equivalent. According to MotorTrend, the U.S. Environmental Protection Agency (EPA) and National Highway Traffic Safety Administration (NHTSA) created MPG-e. In 2007, the Energy Independence and Security Act required that the window sticker on new cars, also known as the Monroney label, include alternative fuel vehicle information. These window stickers had to show a maximum range and mpg-e for vehicles that wouldn’t follow the usual MPG system.
Before 2007, the electric vehicle efficiency was determined by how many kilowatt-hours (kWh) were used for every 100 miles driven. During this time, the government groups found that people in focus groups did not understand kilowatt-hours as a measurement for electric cars or how the EPA calculated efficiency.
Due to this, The EPA created MPG-e to make it easier for people to understand how far the car could go. Miles per gallon equivalent (MPG-e) is a means for people to compare how far an alternate fuel vehicle could go compared to gasoline-powered cars.
How Is MPG-E Calculated?
According to the EPA and MotorTrend, “one gallon of gasoline contains 33.7 kWh of potential energy.” Let’s use the Tesla Model 3 to help explain this further. According to Tesla, the Model 3 Standard Range Plus RWD has a good efficiency rating. At 142 MPG-e combined, the Tesla Model 3 SR can go 142 miles with combined highway/city driving using 33.7 kWh of energy.
“To calculate mpg-e, you’d take miles traveled (output) and divide by the energy consumed as it relates to the energy in a gallon of gasoline (input).” The equation for that is as follows:
MPG-e = total miles driven ÷ (total kWh of energy consumed ÷ 33.7 kWh/gasoline gallon)
An example of this is an electric vehicle that uses 33.7 kWh of electricity to go 100 miles would have an MPG-e rating of 100.
What are some EVs with the best miles per gallon equivalent rating?
Kelley Blue Book rounded up some electric vehicles from 2021 with the best MPG-e rating. This includes the estimated annual fuel cost (using electricity and a 15,000-mile annual estimate) and the estimated range.
- Tesla Model 3 Standard Range Plus: 142 MPGe – $450 – 263 miles
- Tesla Model 3 Long Range AWD: 134 MPGe – $500 – 353 miles
- Hyundai Ioniq Electric: 133 MPGe – $500 – 170 miles
- Tesla Model Y Standard Range: 129 MPGe – $500 – 244 miles
KBB says that MPG-e can be hard to offer a price comparison because the cost of electricity varies by location. To help buyers figure out the cost, new electric vehicles show an estimated annual cost for electricity. Buyers can compare this to the annual cost of fuel.
In conclusion, it will get easier to understand MPG-e the more you look at it. Automakers also make the information easy to find and understand. If you are interested in an electric vehicle, the MPG-e should be easy to find or calculate.