How Much Does It Cost to Charge an Electric Car at Home?

Charging at home is usually the cheapest way to run an electric car, but the actual cost depends on your electricity tariff, your car's efficiency and when you charge. You can work out your own figures with a simple formula and a couple of numbers from your bill and your car.

The simple formula

Cost of a charge = energy added (kWh) × your electricity unit rate. If you add 40 kWh to the battery and your rate is expressed in pence per kWh, multiply 40 by the rate and divide by 100 to get pounds.

Allow for charging losses

Not all the energy from your socket ends up in the battery, because some is lost as heat in the charger and the car. Losses are often around 10 per cent, though they vary. To be accurate, base your calculation on the energy drawn from the wall, which you can measure with a smart meter, a smart charger's app or a dedicated monitor, and not just on the battery capacity.

Cost per mile

Efficiency is usually described in miles per kWh. Many electric cars achieve around 3 to 4 miles per kWh, with variation by model, speed, weather and driving style. To get the cost per mile, divide your unit rate by the miles per kWh. For example, if your rate were 20 pence per kWh and your car did 4 miles per kWh, the cost would be 5 pence per mile. Replace the example numbers with your own.

What changes the cost

• Tariff: special EV tariffs and time-of-use tariffs can offer much cheaper overnight rates. See our guide to time-of-use tariffs.
• Solar panels: charging from your own generation can reduce the cost, particularly with a smart charger that follows solar output. See our solar guide.
• Weather and speed: cold weather, motorway speeds and heavy loads reduce range, so costs per mile rise.
• Standing charge: your overall bill includes standing charges, whatever you use.

Home versus public charging

Public chargers, especially rapid ones, typically cost more per kWh than home electricity, sometimes by a wide margin. Home charging is usually cheaper for regular use, but check current prices because they change. If you cannot charge at home, compare the cost of different networks and subscriptions.

Cost compared with petrol and diesel

To compare, work out the fuel cost per mile for your current car: price per litre divided by the miles per litre you achieve. Compare with your electric cost per mile. The result depends on your tariff, so it can vary between households.

Ways to reduce the cost

1. Charge during cheap periods using the car's or charger's timer.
2. Do not charge to 100 per cent when you do not need to, unless the manufacturer recommends it for longer trips.
3. Maintain tyre pressure and drive smoothly.
4. Compare tariffs regularly. Our switching guide explains how.

For help choosing and installing a charger, see our home EV charger guide.