Direct automotive answer
What is MPGe?
MPGe expresses energy use in miles per gallon equivalent so electricity and other fuels can be compared to the energy in a gallon of gasoline. It is not gasoline MPG. This fuel economy and range answer depends on Energy source, kWh per 100 miles, Drive cycle, Charging losses. Confirm each against the exact vehicle rather than assuming a class-average figure. The sections below break this down further: using it without misleading yourself, why a family range can look extreme, what the unit represents, more useful measures for an owner. 5 related follow-up questions are answered separately below, each with its own conditions attached. This site reviews every answer under a configuration-first standard, verified against FuelEconomy.gov and linked to related fuel economy and range questions for the adjacent decisions this one usually raises. It sits within a fuel economy and range library of 8 related questions, held to the same configuration-first standard.
MPGe, miles per gallon equivalent, expresses electrical energy in gasoline-equivalent terms so an electric or plug-in vehicle can be compared with a combustion one. It is a comparison unit, not a fuel you buy by the gallon.
The conversion rests on the energy content of a gallon of gasoline. A vehicle rated at 100 MPGe uses the energy equivalent of one gallon to travel 100 miles.
Using it without misleading yourself
MPGe compares energy efficiency, not running cost, because electricity and gasoline are not priced on the same basis.
- Compare MPGe against MPGe, never directly against MPG
- Use the annual energy-cost estimate when comparing across fuel types
- Remember electricity prices vary far more by region and time of day than fuel prices
- For plug-in hybrids, note both the MPGe figure and the gas-mode MPG
Why a family range can look extreme
Where one model line contains both a gasoline and an electric version, the combined range mixes MPG and MPGe and can appear enormous. A low-twenties figure alongside a three-digit one.
That range is not an error; it is two different units in one line, which is why matching the fuel-unit context matters before comparing.
What the unit represents
MPGe expresses an electric vehicle's efficiency in terms of the energy in a gallon of gasoline, so it can be placed on the same scale as a combustion vehicle. It is an energy comparison, not a cost comparison.
Because electricity and gasoline are priced completely differently, two vehicles with similar MPGe can cost very different amounts to run, and a vehicle with lower MPGe can be cheaper to fuel if your electricity rate is low.
- Converts electrical energy to a gasoline-equivalent scale
- An energy comparison, not a cost comparison
- Electricity and gasoline pricing are unrelated
- Local rates change the cost conclusion entirely
More useful measures for an owner
Kilowatt-hours per 100 miles is the more directly useful figure, because multiplying it by your electricity rate gives cost per mile immediately. EPA publishes it alongside MPGe.
Charging losses also matter: energy drawn from the wall exceeds energy stored in the battery, and EPA's figures account for that. Home charging at off-peak rates and public DC fast charging can differ several-fold in cost per unit of energy.
- kWh per 100 miles converts directly to cost per mile
- EPA figures account for charging losses
- Off-peak home charging is usually the cheapest energy
- Public DC fast charging often costs several times more
What changes the answer
- Energy source
- kWh per 100 miles
- Drive cycle
- Charging losses
Common follow-up questions
Is 100 MPGe the same as 100 MPG?
Only in energy terms. It means using the energy equivalent of one gallon to travel 100 miles, but electricity is purchased differently, so running cost is a separate calculation.
How do I compare an EV to a gas car on cost?
Use the EPA annual energy-cost estimate for each configuration, then adjust for your own electricity and fuel prices and your annual mileage.
Do plug-in hybrids have both figures?
Yes. They carry an MPGe figure for electric operation and a separate MPG figure for gasoline operation once the battery is depleted.
Does higher MPGe mean cheaper to run?
Not necessarily. MPGe is an energy comparison, not a cost one. Your electricity rate and where you charge determine actual cost per mile.
What figure should I use to estimate charging cost?
Kilowatt-hours per 100 miles. Multiply it by your electricity rate to get cost per mile directly.
Related questions
Fuel economy and range questions and answers: the complete category