EV specifications use several units that sound alike. Once you separate them, they are easy to use.
In this article
- kWh measures energy
- kW measures power
- Efficiency
kWh measures energy
It tells you how much is stored in the battery. A 75 kWh pack holds more than a 60 kWh one, like the size of a fuel tank.
| Unit | What it measures | Car analogy |
|---|---|---|
| kWh | Energy stored | Fuel tank size |
| kW | Rate of power | Pump speed |
| Wh/mile | Consumption | Fuel use |
| Miles per kWh | Efficiency | Miles per gallon |
Figures are typical ranges and vary by car, climate and driving style.
kW measures power
It tells you how fast energy moves. A 150 kW charger delivers energy faster than a 50 kW one.
Energy is the tank, and power is the pump.
Efficiency
Miles per kWh is like miles per gallon. Most EVs return between 2.5 and 4 miles per kWh.
Worth doing
- Find your car’s battery size
- Check your local electricity price
- Track miles per kWh
- Compare running costs
Practical tip
To estimate cost per mile, divide your electricity price by miles per kWh. At 15 cents and 3.5 miles per kWh, that is about 4 cents per mile.
Bottom line
Understanding these units makes every spec sheet clearer.
Specifications, prices and rules change. Confirm current details with the manufacturer or the relevant authority before you buy or repair.
