How Much It Really Costs to Charge an Electric Car at Home

Ask an electric car owner what it costs to charge at home and you will hear anything from "almost nothing" to "more than I expected". Both answers can be true. The real figure depends on your tariff, your car's efficiency, the season, how you charge and a few losses most people never think about. The good news is that once you know those pieces, the calculation takes about two minutes.

I install home chargers for a living, and the question I hear most after "where should it go?" is "what will it cost me?". Here is how to work out the honest answer for your own situation.

The basic formula

The cost of a charge is simply the energy you put in multiplied by what you pay per kilowatt-hour (kWh). If you add 40 kWh to the battery and your electricity costs 0.25 per kWh in your currency, the charge costs 10. To convert that into something comparable with petrol, divide by the distance the energy gives you.

Most electric cars use somewhere between 14 and 22 kWh per 100 kilometres in mixed driving. Smaller hatchbacks are at the low end, heavy SUVs and pickups at the high end. So at 0.25 per kWh, a car using 17 kWh per 100 km costs about 4.25 per 100 km in electricity. Check your car's trip computer for your own real consumption figure, since it reflects your driving rather than an official test.

Charging losses are real

Not all the energy that leaves the wall ends up in the battery. Some is lost as heat in the charger, the car's onboard charger and the battery itself, and some powers the car's systems while it charges. With a typical home wallbox at 7 kW, losses are usually around 10 percent. With a standard three-pin socket at around 2 kW, they are often higher, 15 percent or more, because the car's electronics stay awake for many more hours.

So if your car shows 40 kWh added, the meter may have recorded 44 to 46. When you calculate costs, use the energy from the wall where possible. Many smart chargers and apps report it directly.

Your tariff matters more than your car

The biggest variable is the price you pay for electricity. A flat household tariff might be several times more expensive than an overnight off-peak rate. Many electricity providers now offer EV tariffs with cheap rates for a few hours each night, sometimes a fraction of the daytime price.

Charging the same car on a flat tariff versus a dedicated EV tariff can change the yearly cost dramatically. Before buying a charger, it is worth comparing tariffs and checking whether a cheap overnight window would cover your typical charging needs. For most drivers, five or six hours at 7 kW, which adds 35 to 40 kWh, is more than a day's driving.

Seasons change the numbers

In winter, electric cars use more energy. Cold batteries are less efficient, cabin heating draws power, and winter tyres and wet roads add resistance. Consumption can rise by 20 to 30 percent in cold climates, sometimes more on short trips where the car never warms up properly.

Preconditioning, warming the cabin and battery while the car is still plugged in, helps a lot, because the heat comes from the grid rather than the battery. A heat pump, fitted to many newer EVs, also reduces winter consumption noticeably. If you are working out yearly costs, use an average that includes a few winter months rather than your best summer figure.

Solar panels and self-consumption

If you have solar panels, charging during sunny hours can make some of your driving almost free, apart from the cost of the panels themselves. The catch is timing: many people are at work when the sun shines and the car is not at home. Smart chargers that adjust charging speed to match solar output help when the car is home during the day. Otherwise, a cheap overnight tariff often beats solar for EV charging, and the panels earn more by covering daytime household use.

Is home charging always cheaper than public charging?

The common advice is that home charging is always the cheapest option, and for most drivers on a decent tariff it is. But I think it is worth questioning as a blanket rule.

On an expensive flat tariff, home charging can cost more than some free or subsidised public chargers at supermarkets or workplaces. Some drivers with access to free workplace charging barely need home charging at all. And if you rarely drive far, a standard socket on a cheap overnight rate may be cheaper overall than paying for a wallbox installation you will take years to earn back. The right answer depends on your tariff, your access to other chargers and your driving pattern, not on a general rule.

The cost of the charger itself

A home wallbox and its installation is a one-off cost that should be part of the calculation. Prices vary widely depending on the distance from your fuse board, whether your supply needs upgrading and local rules for earthing and protection. A simple installation near the meter is far cheaper than one that requires trenching across a driveway.

Spread over the life of the charger, which is often ten years or more, the installation cost usually adds little per kilometre. But it matters if you are comparing home charging with a standard socket or public charging for low annual mileage. Our article on questions to ask before buying a used electric car covers how charging access should shape the decision to buy an EV at all.

A worked example

Here is a realistic example for a driver covering 12,000 km per year:

• Average consumption: 17 kWh per 100 km, including winter.
• Energy at the battery: about 2,040 kWh per year.
• With 10 percent charging losses: about 2,250 kWh from the wall.
• On a 0.10 off-peak rate: about 225 per year.
• On a 0.30 flat rate: about 675 per year.

The same car, the same driving, and a threefold difference purely from the tariff. That is why the tariff deserves more attention than almost anything else.

How to track your real cost

Most smart chargers and EV apps can log every session with energy and cost. If yours does not, a simple spreadsheet with the date, kWh from the wall and the rate is enough. After two or three months you will have a far more accurate picture than any online calculator can give you.

Battery health also affects long-term running costs, which we cover in what happens to an EV battery after eight years. For more on charging, see our EV Charging section.