Electric Car Efficiency Converter
Convert electric vehicle efficiency between miles per kWh, kWh per 100 miles, km per kWh, kWh per 100 km, Wh per mile and MPGe.
Change the values and press Calculate to work out your own figures.
Enter an electric car's efficiency, choose its unit and the unit you want. The answer is exact until it is shown, and the same value appears in every other unit.
Show the working
- 25 kWh/100 mi = 6.437376 km/kWh
- 6.437376 km/kWh = 4 mi/kWh
How to use it
Type an electric car's efficiency, choose the unit it is in and the unit you want, then press Calculate. You can type decimals, fractions such as 3/8, mixed numbers such as 1 1/2, very large or small numbers such as 2.5e6, and simple sums such as 2*3. Swap exchanges the two units.
The answer is worked out with exact fractions and only rounded for display, to 12 significant figures. Below it you get the same value in every other unit on the list, and Show the working gives the factor that was used.
Key definitions
kWh/100 mi = 100 ÷ (mi/kWh) 1 mi/kWh = 1.609344 km/kWh MPGe = (mi/kWh) × 33.705
Two ways round
Efficiency can be given as distance per energy (miles per kWh, higher is better) or energy per distance (kWh per 100 miles, lower is better). They are reciprocals: 4 miles per kWh is 25 kWh per 100 miles. The converter handles both directions.
MPGe
Miles per gallon equivalent lets you compare an electric car with a gasoline one. The EPA counts 33.705 kWh of electricity as one gallon of gasoline, so a car that goes 4 miles per kWh rates about 135 MPGe.
Questions
What is good efficiency for an electric car?
Many compact EVs manage 3.5 to 4.5 miles per kWh (about 22 to 29 kWh per 100 miles); large trucks and SUVs often use more.
How is MPGe calculated?
Miles per kWh multiplied by 33.705, the EPA's number of kWh equivalent to one gallon of gasoline.
Formulas
result = (value × f(from) + o(from) − o(to)) ÷ f(to)
Sources
Limitations
- Only the units listed are supported here; other electric-car-efficiency units arrive with later M4 slices.