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MPGe calculator

Turn an electric car's energy use into miles per gallon equivalent, or an MPGe figure back into kWh per 100 miles. Also shows miles per kWh and the metric units.

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MPGe uses the EPA definition: 33.705 kWh of electricity counts as one gallon of gasoline.

What MPGe means

MPGe, miles per gallon equivalent, lets you compare an electric car's energy use with a gas car's mpg. The EPA defines one gallon of gasoline as equal to 33.705 kWh of electricity. MPGe is how many miles the car goes on 33.705 kWh.

It compares energy, not cost. A gallon of gas and 33.705 kWh of electricity rarely cost the same, so for money use the EV vs gas calculator.

The units

kWh/100 mi: energy used per 100 miles. Lower is better. This is the figure the EPA shows next to MPGe on the window sticker.
MPGe: miles per 33.705 kWh. Higher is better.
mi/kWh: miles per kWh, the figure many car displays show. Higher is better.
kWh/100 km and km/kWh: the same in metric.

The formulas

MPGe = 3,370.5 ÷ kWh per 100 mikWh per 100 mi = 3,370.5 ÷ MPGe mi/kWh = 100 ÷ kWh per 100 mi

3,370.5 is 100 × 33.705. For metric, divide kWh/100 mi by 1.609344 to get kWh/100 km.

Worked example

An electric car uses 30 kWh per 100 miles. 3,370.5 ÷ 30 = 112.4 MPGe. It goes 100 ÷ 30 = 3.33 miles per kWh, and uses 30 ÷ 1.609344 = 18.64 kWh per 100 km, or 5.36 km per kWh.

The other way: 100 MPGe is 3,370.5 ÷ 100 = 33.71 kWh per 100 miles. 4 mi/kWh is 25 kWh/100 mi, or 134.8 MPGe.

Which energy is counted

The EPA sticker figures count energy from the wall outlet, so charging losses are included. A car's own display usually counts energy out of the battery, which reads better. Convert the number you have, but compare like with like. A car that shows 4.0 mi/kWh on its display will not match a sticker figure of 134.8 MPGe exactly, because the two count energy at different points.

Questions

How do you calculate MPGe?

Divide 3,370.5 by the kWh used per 100 miles. A car that uses 30 kWh/100 mi rates 112.4 MPGe.

How many kWh is 1 gallon of gas?

For MPGe, the EPA counts one gallon of gasoline as 33.705 kWh. So 100 MPGe means 33.71 kWh per 100 miles.

How do I convert mi/kWh to MPGe?

Multiply the miles per kWh by 33.705. 4 mi/kWh is 134.8 MPGe.

Is a higher MPGe better?

Yes. A higher MPGe, a higher mi/kWh and a lower kWh per 100 miles all mean the car uses less energy for the same distance.