The Basics of Calculating MPGe
When you’re comparing fuel efficiency for conventional vehicles, MPG (Miles Per Gallon) is all you need to know. For hybrids and all-electrics, you need to start taking MPGe (Miles Per Gallon equivalent) into account. So:
- What does MPGe mean?
- How is MPGe calculated?
- How should you shop using MPGe ratings?
We’ve broken down each question to get you up to speed on MPGe.
What Does MPGe Signify?
When hybrid and electric vehicles started hitting the roads, federal agencies were faced with something of a quandary: how could they let shoppers compare energy costs without the conventional MPG rating? An all-electric vehicle doesn’t use “gallons” of anything, and a hybrid supplements its fuel with electric input, so an easy apples-to-apples standard had to be developed.
That’s where MPGe comes from: it stands for “Miles Per Gallon equivalent.” Instead of using unfamiliar terms, such as kilowatts and kilowatt-hours, the MPGe standard is easy enough to understand. It simply refers to the number of miles a vehicle can travel using a quantity of electricity, with the energy content identical to one gallon of gasoline.
How is MPGe Calculated?
MPGe is a virtual calculation. The EPA conducts test cycles and assumes averages for key variables, including electricity rates and fuel costs. It sounds like a hit-or-miss process, but it’s used across all electric and hybrid models to provide a relatively accurate impression of how each one will behave.
Essentially, if the EPA rates a certain hybrid or electric vehicle at 100 MPGe, it means its operating efficiency is on par with a fuel-based car that gets 100 mpg.
How Should You Shop Using MPGe Ratings?
- All-Electric: If you’re shopping for a battery-electric car, the distance it covers from full battery to flat is its MPGe rating – this goes on the sticker in place of the traditional MPG figure. For example, the Ford Focus Electric makes up to 107 combined MPGe.
- Hybrid: When you’re shopping for a hybrid, you’ll find two types of rating; traditional MPG shows how far a vehicle goes under conventional power, while MPGe shows how far it goes when the battery pack is used.