About the MPGe Calculator
This MPGe calculator converts electric-vehicle efficiency between all the units you will see on window stickers, in car apps and in reviews: miles per gallon equivalent (MPGe), kilowatt-hours per 100 miles, miles per kWh, watt-hours per kilometre and kWh per 100 km. Choose the unit you have, type the number, and every other unit is calculated instantly.
MPGe is the EPA’s way of comparing electric cars with gasoline cars. It uses the federal definition that one gallon of gasoline contains the same energy as 33.705 kWh of electricity, so an EV that travels 100 miles on 33.705 kWh is rated 100 MPGe. Most drivers find kWh per 100 miles or miles per kWh more useful for working out charging costs, so the calculator also shows the cost per mile at your electricity price.
The cost-equivalent MPG answers a different question: what gas mileage a gasoline car would need to cost the same per mile at the fuel price you enter. Note that EPA label figures include charging losses (energy taken from the wall), while the efficiency shown on a car’s dashboard is usually measured from the battery and looks a little better.
With the default inputs, the mpge is 112.4 MPGe. Change any value above to recalculate instantly.
How to use the mpge calculator
- 1Choose the unit your efficiency figure is in.
- 2Enter the number from the window sticker, review or car app.
- 3Enter your electricity price per kWh (and gas price for comparison).
- 4Read every equivalent unit, the cost per mile and the cost-equivalent MPG.
Formula and method
Every unit is first converted to kilowatt-hours per mile. MPGe divides the EPA energy equivalent of one gallon of gasoline — 33.705 kWh, defined in 40 CFR 600.002 — by the energy the car uses per mile. Miles per kWh is the reciprocal of kWh per mile, and the metric units divide by 1.609344 km per mile.
Cost per mile is kWh per mile multiplied by your electricity price. The cost-equivalent MPG divides the gasoline price by that cost per mile: it is the fuel economy a gas car would need to cost the same per mile, which depends on your local prices, unlike MPGe, which compares energy only.
- 33.705
- kWh of electricity equivalent to one gallon of gasoline (EPA)
- kWh/100 mi
- Energy used to drive 100 miles
- 1.609344
- Kilometres per mile
Worked examples
30 kWh per 100 miles
30 kWh per 100 miles is 0.3 kWh per mile, so MPGe = 33.705 ÷ 0.3 = 112.4. That equals 3.33 mi/kWh or about 186 Wh/km. At 17¢ per kWh each mile costs 5.1¢, the same as a 69 mpg gas car at $3.50 a gallon.
Window sticker says 120 MPGe
120 MPGe means 33.705 ÷ 120 = 0.2809 kWh per mile, or 28.1 kWh per 100 miles. That is about 3.56 miles per kWh, or 17.5 kWh per 100 km.
European figure: 165 Wh/km
165 Wh/km × 1.609344 = 265.5 Wh per mile, or 26.6 kWh per 100 miles, which converts to about 127 MPGe and 3.77 mi/kWh. At 30¢ per kWh each mile costs about 8¢.
Frequently asked questions
What does MPGe mean?+
MPGe stands for miles per gallon of gasoline-equivalent. It shows how far a vehicle goes on electricity containing the same energy as one gallon of gasoline, which the EPA defines as 33.705 kWh. It allows EVs to be compared with gas cars on energy use.
How do I convert kWh/100 miles to MPGe?+
Divide 3,370.5 by the kWh per 100 miles figure. For example, 25 kWh/100 mi is 3,370.5 ÷ 25 = 134.8 MPGe, and 35 kWh/100 mi is about 96 MPGe. Lower kWh/100 mi means higher MPGe.
What is a good MPGe or miles per kWh?+
Efficient small EVs and sedans are typically rated around 120–140 MPGe (about 3.5–4.2 mi/kWh). Large electric SUVs and pickups are often in the 70–90 MPGe range (around 2–2.7 mi/kWh).
Why is my car’s mi/kWh higher than the EPA rating?+
EPA ratings measure energy drawn from the wall, including charging losses of roughly 10–15%, while most dashboards report energy drawn from the battery. Weather, speed, and heating or cooling also change real-world efficiency.
Does MPGe tell me how much an EV costs to run?+
Not directly, because electricity and gasoline prices vary. Use kWh per mile times your electricity price instead; this calculator shows that cost per mile and the gas MPG that would cost the same.