Nov 4, 2022
mercedes EQS at a charging station

Miles per Gallon Equivalent, or MPGe, is a metric used for gauging fuel efficiency for electric vehicles. It was developed in 2010 by the Environmental Protection Agency as a means of helping drivers better comprehend the abilities of a battery-operated vehicle. 

EQS Charging at home

How is MPGe Calculated?

MPGe is a calculation of how many miles an electric vehicle can drive on the same amount of energy contained in one gallon of gasoline. The unit of measurement of energy for an electric vehicle is the kilowatt hour, abbreviated kWh. In one gallon of gasoline, there are approximately 33.7 kWh of energy.  A vehicle that can travel 60 miles every 33.7kWh will thus have a rating of 60 MPGe. 

In the next section, we will show you how to calculate MPGe using the vehicle’s range and battery capacity. 

Range vs MPGe on an EV

EQS charging port
The charging plug on a Mercedes EQS Sedan. Image courtesy of Mercedes-Benz USA.

When many drivers are first considering an electric vehicle, they may find themselves comparing the “range” given by the manufacturer. This is the distance your car can drive in optimum conditions on a 100 percent battery charge. 

Knowing the range is a good start, but it does not help you know how many more miles you can drive on a battery that is not fully charged. How far could you drive on, say, an 80 percent battery charge? 

This is where the MPGe comes in. To calculate a vehicle’s MPG3, we start with the battery capacity. This is essentially the fuel tank for the EV and, like a fuel tank, it has a limit. 

Let’s use the Mercedes Benz EQS 450 as an example. The EQS has a battery capacity of 107.8 kWh. If we divide this number by our aforementioned gallon-of-fuel equivalent of 33.7 kWh, we get about 3.2 gallons. 

Now, we take the given range for the Mercedes EQS 450, which is 350 miles.

350 miles/3.2 gal = 109.375 MPGe  

This is a more useful number, since we can use it to determine approximately how far we can go on a specific level of charge. If we have a 3.2 “gallon” tank that is at 80 percent, we are down to 3.2 x 0.8, or 2.56 gallons. Now we know we can get 109.375 miles per gallon, so we multiply this number by 2.56, which is 280 miles. 

Again, this number is an approximation. When tested, the EPA actually found that the MPGe for the EQS 450 was 97. This is 12 miles less than our estimation. The discrepancy can be attributed to various factors, like temperature. You will therefore want to give yourself a little wiggle room when you determine how much farther you can drive on a certain level of charge. 

Questions About Your Electric Mercedes?

Stop by our dealership or call any time if you have questions about an EV you’ve purchased at Mercedes Benz of Littleton. Our knowledgeable staff are more than happy to help you make the most of your new vehicle.