Electric Vehicle Range / Efficiency Unit Conversions

A simple calculator to convert between EPA, MPGe, Wh/mi, kWh/mi, mi/kWh, Wh/km, kWh/km, km/kWh

Select Unit:
MPGe
   
Enter Value:


Unit Value
MPGe
Wh / mi
kWh / mi
kWh / 100 mi
mi / kWh
Wh / km
kWh / km
kWh / 100 km
km / kWh

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What is the difference between kW and kWh?

Think of kW (Kilowatts) as speed and kWh (Kilowatt-hours) as capacity. In EV terms, kW is how fast you are charging, while kWh is the total energy your battery holds.

Why do some values decrease while others increase?

Units like mi/kWh measure distance (higher is better), while Wh/mi measures energy consumption (lower is better). When you become more efficient, your mi/kWh goes up, but your Wh/mi goes down.

Is a lower Wh/km better?

Yes. Wh/km measures how much energy is used to move the car. A lower number means the car is more efficient. For example, 150 Wh/km is more efficient than 250 Wh/km.

Why do some values look like shifted versions of each other?

Many of these numbers represent the same data with a shifted decimal point. For example, kWh/mi is simply Wh/mi divided by 1,000. Units like Wh/mi and Wh/km are the most "precise" because they provide whole-number granularity for trip planning, whereas others are shifted to make them easier to read or compare to manufacturer ratings.

Why use Wh/mi instead of MPGe?

Wh/mi (or Wh/km) provides more precision for trip planning. It tells you exactly how much battery energy is consumed per unit of distance, which is more helpful for calculating real-world range than the EPA's MPGe rating.

Does my speed affect these numbers?

Yes, significantly. Efficiency units like Wh/mi or Wh/km are not static. Driving at higher speeds increases air resistance, which raises your energy consumption (higher Wh/mi) and lowers your range.

How do I use these numbers to see my actual range?

To find your estimated range, divide your battery's usable capacity (in kWh) by your efficiency. For example, if you have a 75 kWh battery and your average efficiency is 0.30 kWh/mi, your estimated range is 250 miles.

Why is my car showing different numbers than this calculator?

Your car displays real-time efficiency based on your driving habits, weather, and terrain. This calculator provides the mathematical equivalents based on standard constants; your car shows what you are actually achieving.


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