Efficiency · 4 min read
How MPGe works
33.7 kWh is one gallon of gas. Here's what that means for your bill.
Gas cars are rated in miles per gallon. EVs don't burn gallons, so the EPA invented MPGe, miles per gallon equivalent: how far the car goes on the same amount of energy that's in one gallon of gasoline.
The one number to remember: 33.7
A gallon of gasoline holds about 33.7 kWh of energy. So an EV rated at 112 MPGe goes 112 miles on 33.7 kWh, or about 30 kWh per 100 miles.
The EPA measures that energy at the wall outlet, so the losses from charging are already in the number.
Why kWh/100 mi is the more useful number
MPGe is good for comparing EVs to each other. It's bad for working out cost, because you don't buy electricity by the gallon. Your utility bill is in kWh. Multiply a car's kWh per 100 miles by your rate and you have the cost of 100 miles.
Lower kWh/100 mi is better, the same way a higher MPGe is. Small, aerodynamic cars land around 24 to 28. Big SUVs and trucks run 40 to 50.
What MPGe leaves out
- Price. 112 MPGe at 13¢/kWh costs half as much per mile as the same car at 26¢/kWh.
- Public fast charging. DC fast chargers often bill 40 to 60¢/kWh, three times typical home power.
- Winter. Ratings come from mild-weather tests. See why range drops in winter.
Each model page runs these numbers for your state. Find a model to try it.