How Does MPGe Compare to MPG?

How Does MPGe Compare to MPG? - Germain Cars Group Site

From jaw-dropping efficiency to exhilarating performance, it’s easy to see the growing appeal of hybrid and electric vehicles. Their outstanding refinement and responsiveness make them an excellent choice for commuting, especially when you consider the fuel savings compared to a conventional gasoline-powered vehicle. Speaking of fuel savings, one of the most common questions that potential hybrid and EV shoppers tend to ask us is “what’s the difference between MPG and MPGe”? While it might seem confusing at first, these two measurements of fuel economy are actually quite easy to understand once you know the specifics. Our team at the Germain Motor Company has created this handy MPG vs MPGe reference guide that lists all the differences and similarities between these two fuel economy measurements.

MPGe Window Sticker

MPGe Explained

As you get started researching potential hybrid or electric vehicles, it’s likely that you’ve come across the term “MPGe” in relation to its efficiency. MPGe stands for “Miles Per Gallon Equivalent”, similar to the familiar MPG or “Miles Per Gallon” used to describe the fuel economy of a gasoline or diesel-powered vehicle. Traditional MPG is quite easy to understand since it refers to how many miles your vehicle can drive using one gallon of fuel. Since certain hybrids and all-electric vehicles don’t always need conventional fuel to operate, MPGe is used for calculating the energy use of electrified vehicles. We’ll cover this concept in greater detail below.

Mercedes-EQ Charging

What Does kWh Mean?

When the Environmental Protection Agency (EPA) created the MPG equivalent, it used an established energy standard of 115,000 BTUs (British thermal units) per gallon of gasoline. In other words, this equates to the same amount of energy generated by igniting 1 gallon of unleaded gasoline. Generating this same amount of heat requires 33.7 kilowatt hours of electricity. In short, 1 gallon of gasoline produces the identical amount of heat energy as 33.7 kilowatt hours of electricity.

In order for an electric vehicle to receive an MPG equivalency of 100 MPGe, it would need to travel 100 miles on 33.7 kilowatt hours of electricity (equal to 1 gallon of gasoline). Now, imagine a different EV can travel that same 100 miles of distance but it uses 32 kWh of electricity. Since it uses slightly less electricity, it would be rated at 105 MPGe, more efficient than the first EV. Similar to conventional MPG ratings, the EPA measures MPGe using city, highway, and combined categories.

Porsche Taycan

Driving Range Ratings for Electric Vehicles

Another important piece of information listed on the EPA sticker for an electric vehicle is its range rating. An EV’s driving range specifies how far the vehicle is rated to drive using solely electric power. For a hybrid or plug-in hybrid vehicle, this rating also includes the range of the gasoline engine combined with a fully-charged electric battery.

Remember, the EPA bases these calculations on the fact that an average EV will only have 90% of a fully charged battery. This means that range ratings should be used more as a guideline as opposed to a concrete fact. Also important to remember is that MPGe should be treated just like MPG in the sense that these estimates can vary widely based on a number of factors. Your use of the throttle, climate conditions, terrain type, and cargo load are all involved in determining the exact MPGe that your vehicle will get.