Electric cars . . . Energy-efficient tech, endless new possibilities. The future where the motoring world is headed.
But it's also a bit true that you're driving into a world packed with some technical jargon and terminology.
Read any electric car review, or look at any of the electric car leasing deals on our site, and you're bound to see stats using kW and kWh.
In the EV world, kWh refers to the size/capacity of the car battery, and kW refers to the power used to charge that battery.
Or if we imagine that an electric car battery is a swimming pool, then kWh is the amount of water the pool can hold, and kW is the rate at which water will flow into the pool.
Let’s make a splash and dive into some more detail.
kW (Kilowatts)
If you want a more powerful electric car, choose one with a higher kW
You probably know about kilowatts from everyday electrical devices (laptop, electric heater etc.), and in terms of electric cars as well, the kW rating is basically a measure of power: the speed of a car or of its EV charger. It's the power output of the electric motor or the power of the charging system. So if an electric car has a motor rated at 100 kW, it can produce up to 100 kilowatts of power when accelerating.
In the same way that a petrol or diesel car's engine performance depends on its horsepower (hp) output, an electric car's power is directly tied to its kW output.
Also, knowing the kW output of a charging stations can help you figure out how long it will take to recharge your vehicle.
The examples below should help give you an idea. Notice how the more premium or 'flashy' electric cars have a higher kW rating:
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Dacia Spring – 48kW
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Nissan Leaf – 110 kW
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BYD Dolphin – 150 kW
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Ford Mustang Mach-E GT – 358 kW
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Tesla Model Y – 378kW
And an example of different kW battery options for a vehicle on LeaseLoco:
kWh (Kilowatt-hours)
If you want an electric car with a longer range, choose one with a higher kWh
kWh or a kilowatt hour is a measure of energy consumption. It represents the total amount of energy consumed or stored over a certain period of time. In terms of electric vehicles, it refers to the battery capacity.
So the more you drive the car after it has been charged, the more you use up electrical power from the battery, meaning the kWh will drop from 54 kWh to 51, 50, 49, etc. etc, with more electricity consumption.
The higher the kWh rating, the more energy the battery can store, and the further the vehicle can travel without you having to plug in on the go.
A higher kWh rating usually means an electric car can travel longer on a fully-charged battery. The bigger the battery is in terms of kWh capacity, the more electricity it can store, and the more electricity it can store, the longer the vehicle's range.
The examples below should help give you an idea:
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Dacia Spring – 39kWh / 168 miles range
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Nissan Leaf – 59kWh / 239 miles range
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Kia e-Niro – 64kWh / 285 miles range
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Rolls-Royce Spectre – 103kWh / 329 miles range
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Mercedes-Benz EQS – 108.4kWh / 453 miles range
Will My Electricity Bill Be in kW or kWh?
This is assuming that you've got access to a wall-box and are able to charge your electric car at home.
Your energy costs on your electricity bill might show the rate at which you used energy in kilowatts (kW) at certain times, but the total consumption will be expressed in kilowatt-hours (kWh) of electricity.
Summary
So when it comes to kW vs kWh, they both measure energy, but in different ways. What it boils down to is that more kW means faster charging and higher performance (think Teslas and Mustangs), whilst more kWh means better battery capacity and range.
See this in action over on our electric car leasing deals, or if you're unsure about other things charging-related, head over to our electric car charging guide.
FAQs
What is the difference between kW and kWh in electric cars?
Kilowatts (kW) refers to how much power is used to charge an electric car's battery, whilst kilowatt hour (kWh) refers to the size/capacity of the electric car's battery. Generally, more kW means a more powerful electric car, and more kWh means an electric car with longer range.
Which is bigger, kW or kWh?
kW vs kWh, or asking which one is larger, is maybe not a fair question as they basically measure different things. Kilowatts/kW are units of energy and they measure how much energy is available. But generally speaking, you could say that kWh is the larger measurement as an umbrella term.
How far does 1kWh get you in an electric car?
On average, a modern electric car has a rate of 3 to 3.5 miles per kWh. On the low end, some will only do 2.5 miles per kW.