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EV Efficiency & MPGe Calculator
Type in your electric car's efficiency and your electricity price to instantly see its MPGe, cost per mile, and how it stacks up against a gas car. Everything runs in your browser.
The short answer: MPGe = miles per kWh × 33.7. The EPA counts 33.7 kWh of electricity as the energy in one gallon of gasoline, so a car that travels 3.5 miles per kWh is rated at about 118 MPGe. Enter your own numbers below.
How the calculation works
The tool first converts whatever unit you pick into a single canonical figure — miles per kWh — then derives everything else from it:
- MPGe = miles per kWh × 33.7 (the EPA gasoline-equivalent constant).
- kWh per 100 miles = 100 ÷ miles per kWh.
- Wh per mile = 1000 ÷ miles per kWh.
- Cost per mile = electricity price ÷ effective miles per kWh, where the effective figure is reduced by your charging-loss percentage because the wall meter records more energy than reaches the battery.
Rated efficiency describes energy at the battery; the charging-loss field lets the cost side reflect the extra energy your home meter actually bills you for. Leave it at zero if you only want the rated numbers.
Typical EV efficiency, at a glance
These are representative rated figures. Your trim, wheels, and climate will move them, so always confirm with your own dashboard readout.
| Example vehicle type | mi/kWh | kWh/100 mi | ≈ MPGe |
|---|---|---|---|
| Efficient compact EV | 4.2 | 24 | 142 |
| Mainstream sedan | 3.7 | 27 | 125 |
| Mid-size crossover | 3.1 | 32 | 104 |
| Large SUV / performance | 2.4 | 42 | 81 |
| Electric pickup truck | 1.9 | 53 | 64 |
Questions people ask
What does MPGe mean?
MPGe stands for miles per gallon of gasoline-equivalent. The EPA treats 33.7 kWh of electricity as holding the same energy as one US gallon of gasoline, so MPGe lets you compare an electric car's energy use against a gas car on one scale. To get it, multiply your car's miles per kWh by 33.7.
How do I convert kWh per 100 miles to mi/kWh?
Divide 100 by the kWh figure. A car rated at 28 kWh/100 mi does 100 / 28 = 3.57 mi/kWh. Multiply that by 33.7 and you get about 120 MPGe.
Why is my real-world efficiency worse than the rated number?
Cold weather, highway speeds, hills, heavy loads, roof racks, and running the heater or A/C all raise energy use. Charging losses of roughly 8-15% also mean the wall meter records more kWh than reach the battery, which lowers your real cost-per-mile efficiency.
What electricity price should I use?
Use your marginal home rate in dollars per kWh from your utility bill. In the US the residential average is roughly $0.16-$0.18/kWh, but time-of-use plans, EV night rates, and public DC fast chargers can be much lower or much higher.
Is a higher or lower number better?
For mi/kWh and MPGe, higher is more efficient. For kWh/100 mi and Wh/mi, lower is more efficient because you are using less energy to cover the same distance.
Want the full method, including how charging losses and cold weather change the result? Read the EV efficiency guide. To see when electric beats gas on running cost, see electric vs gas cost per mile.
- What does MPGe mean?
- MPGe stands for miles per gallon of gasoline-equivalent. The EPA treats 33.7 kWh of electricity as holding the same energy as one US gallon of gasoline, so MPGe lets you compare an electric car's energy use against a gas car on one scale. To get it, multiply your car's miles per kWh by 33.7.
- How do I convert kWh per 100 miles to mi/kWh?
- Divide 100 by the kWh figure. A car rated at 28 kWh/100 mi does 100 / 28 = 3.57 mi/kWh. Multiply that by 33.7 and you get about 120 MPGe.
- Why is my real-world efficiency worse than the rated number?
- Cold weather, highway speeds, hills, heavy loads, roof racks, and running the heater or A/C all raise energy use. Charging losses of roughly 8-15% also mean the wall meter records more kWh than reach the battery, which lowers your real cost-per-mile efficiency.
- What electricity price should I use?
- Use your marginal home rate in dollars per kWh from your utility bill. In the US the residential average is roughly $0.16-$0.18/kWh, but time-of-use plans, EV night rates, and public DC fast chargers can be much lower or much higher.
- Is a higher or lower number better?
- For mi/kWh and MPGe, higher is more efficient. For kWh/100 mi and Wh/mi, lower is more efficient because you are using less energy to cover the same distance.