Charging an electric car at home is the cheapest way to fuel a car there is, but only on the right tariff. The same car can cost 2p a mile or 8p a mile depending purely on when you plug in, and relying on public rapid chargers can cost more per mile than petrol. This guide works out the actual figures so you can see where you sit.
The short answer. Charging is just buying electricity: the cost of a full charge is your battery size in kWh multiplied by your price per kWh. A typical car returns about 3.5 miles per kWh, so your cost per mile is simply your unit rate divided by 3.5. On a cheap overnight EV tariff that works out around 2p a mile; on a standard daytime rate around 7p a mile; on a public rapid charger more like 23p a mile.
What a full charge costs
To charge from empty to full you pay for roughly the battery's usable capacity in kilowatt-hours, plus about 10 per cent on top for charging losses, which home AC charging always carries. The table below uses three real-world unit rates current in mid 2026: an off-peak EV rate of 8p, which is typical of dedicated EV tariffs running between about 7p and 9p; the standard price-cap rate of 26p; and a public rapid rate of 79p per kWh. Your own rates will differ, so put your real numbers through the running cost calculator.
| Battery size | Off-peak (8p) | Standard (26p) | Public rapid (79p) |
|---|---|---|---|
| 40 kWh (small EV) | £3.20 | £10.40 | £31.60 |
| 60 kWh (mid-size EV) | £4.80 | £15.60 | £47.40 |
| 80 kWh (large EV) | £6.40 | £20.80 | £63.20 |
Figures are the energy cost of a full charge at the rates above, before the roughly 10 per cent charging losses. In practice you rarely charge from completely empty to completely full, so a typical top-up costs less than the figures shown.
The cost per mile, and how far a charge goes
Cost per mile is the more useful number, because it lets you compare an EV directly with petrol. At about 3.5 miles per kWh, a full 60 kWh battery takes you roughly 210 miles, so you can read the cost of any journey straight off your unit rate.
| Where you charge | Cost per mile | Cost of 100 miles |
|---|---|---|
| Home, off-peak EV rate (8p) | 2.3p | £2.29 |
| Home, standard rate (26p) | 7.4p | £7.43 |
| Public rapid charger (79p) | 22.6p | £22.57 |
| Petrol car at 50 mpg (£1.59/litre) | 14.4p | £14.43 |
Worked at 3.5 miles per kWh for the EV and 50 miles per gallon at £1.59 a litre for the petrol car. Cold weather, motorway speeds and a heavy right foot all push the EV figures up, just as they do a petrol car's.
Rates checked June 2026: standard rate from the Ofgem price cap for July to September 2026 (26.11p per kWh); off-peak figure typical of dedicated EV tariffs (Intelligent Octopus Go, EDF GoElectric, British Gas EV, broadly 7p to 9p in the overnight window); public rapid average 79p per kWh from the Zapmap price index; petrol at the June 2026 UK average of about 159p a litre. Always check your own tariff and local pump price.
Why the tariff is everything
Look again at that table. The car has not changed between the first two rows, only the time of day you charged. A standard daytime rate makes an EV reasonably cheap; a dedicated overnight EV tariff, where the unit price in the small hours is a fraction of the daytime rate, drops the cost per mile to a level petrol cannot touch. This is the single biggest lever you control, and it dwarfs anything to do with the car itself. Getting a smart meter and moving onto a time-of-use or EV tariff is close to essential to get the most from charging at home. It is worth comparing the EV tariffs on offer, because the size of the off-peak window and the gap between the cheap and peak rates vary a good deal between them, all covered in the EV tariffs explained guide.
Home charger versus the three-pin plug
You can charge from an ordinary three-pin socket, but it is slow, adding only around 8 miles of range an hour, and a domestic socket is not designed for many hours of heavy continuous draw. A dedicated 7kW home wall charger is far quicker at roughly 25 to 30 miles of range an hour, safer for sustained charging, and crucially can be set to run only during your cheap off-peak window automatically. For anyone charging regularly at home, a proper charger usually earns its keep through convenience and by making off-peak charging effortless rather than something you have to start and stop by hand at midnight. The 3-pin plug versus 7kW wallbox guide works through who genuinely needs a wallbox and who can manage on the cable that came with the car.
Home versus public charging
Home off-peak charging is the cheapest option by a wide margin, and as the cost-per-mile table shows, public rapid charging can actually cost more per mile than running a petrol car. You are paying for speed, convenience and the cost of the infrastructure. That is a fair deal as an occasional top-up on a long journey, but a driver who relies on rapid chargers for everyday miles throws away most of the running-cost advantage an EV should give. The model that saves the most is simple: do the bulk of your charging slowly and cheaply at home overnight, and use public chargers only to extend range on longer trips. The home versus public charging guide works the comparison through in full, and if you have no driveway the charging without a driveway guide covers your options.
How it compares with petrol
On an off-peak home tariff an electric car is dramatically cheaper to fuel than petrol, around six times cheaper per mile in the worked example above. Even on a standard daytime rate it is usually cheaper, though by a smaller margin. The fuel saving is one of the clearest running-cost advantages of going electric, but it should be weighed against the whole picture of buying and owning the car rather than taken alone. A fuller side-by-side of fuel, servicing and the rest is in the EV versus petrol running cost guide, and the year of charging versus a year of petrol guide puts real annual figures on it. If you are still running a combustion car, the habits on the hypermiling and fuel and driving pages are the way to trim its thirst; if you have gone electric, the equivalent skill is simply charging at the right time, which the best time to charge guide covers in detail.
The bottom line
Charging an electric car at home costs whatever your unit rate says it does, and the rate is yours to choose. On a cheap overnight tariff a full charge of a mid-size car is a few pounds and your motoring costs about 2p a mile, which nothing burning petrol can match. Charge at the standard daytime rate and it is still cheaper than petrol, just less spectacularly. Lean on public rapid chargers for daily miles and you give the advantage back. Sort the tariff, charge overnight, and home charging is as cheap as motoring gets.