If you've ever shopped for a car, you know the first thing you look for is its miles per gallon. Is the car fuel efficient or a gas guzzler? But with EVs, there is no mpg. However, there is something called miles per gallon equivalent, or MPGe.
A gallon of gas will generate about 115,000 BTUs of energy, according to the Environmental Protection Agency. The MPGe for an electric vehicle tells you how far it can go on those 115,000 BTUs. (See the EPA's window sticker for EV cars.)
For example, the gas-fueled 2016 Ford Focus gets 26 miles per gallon in the city and 36 mpg on the highway. The all-electric 2016 Ford Focus gets the equivalent of 110/99 miles per gallon.