By the Home Savings Calculator team · 29 August 2026 · 7 min read
The cost of a charge is the energy you put in multiplied by the price per kWh. For a typical 65kWh battery, at the rates our calculator uses for the UK:
| Where you charge | Price per kWh | Empty to full | 10% to 80% | Per mile |
|---|---|---|---|---|
| Home, EV overnight tariff | 8.5p | £5.53 | £3.87 | 2.4p |
| Home, standard price-cap tariff | 26.32p | £17.11 | £11.98 | 7.5p |
| Public rapid charger | 80p | £52.00 | £36.40 | 22.9p |
Per-mile figures assume 3.5 miles per kWh, a fair year-round average for a mid-size EV. Most people rarely charge from empty — topping up from 10% to 80% is the more realistic session, and rapid chargers slow sharply above 80% anyway. For your own car, mileage and tariff, the EV charging cost calculator works it out in a few seconds.
An overnight home tariff can be a small fraction of the price of public rapid charging. Run the same annual mileage entirely on one or entirely on the other and the yearly cost can differ several times over.
This is the first thing to establish honestly. Not what you intend to do — what you will actually do, given where you park and how far you drive. A driver without off-street parking is in a genuinely different economic position, and no amount of efficiency makes that up.
Set your real charging split in the EV charging cost calculator before anything else. It changes the answer more than any other input on the page.
If you charge at home, a dedicated EV or time-of-use tariff is usually the single biggest saving available — often a several-hour overnight window at a fraction of the day rate. Charging on a standard flat tariff throws most of that away.
Read the whole tariff, though. Some pair a very cheap night rate with a day rate above the standard one, which costs you if the rest of the house uses much electricity in daylight. Check it against your overall electricity bill, not just the car.
Miles per kWh drops in cold weather — heating the cabin costs real energy, and battery chemistry is less willing when cold. A car that manages 4 mi/kWh in June may do 3 in January.
Motorway speed hurts too, for the same aerodynamic reasons petrol cars suffer. Use an observed annual average rather than the manufacturer figure, or the whole calculation drifts optimistic.
Compare energy against fuel, and keep everything else out. Purchase price, insurance, servicing, depreciation and tax are real, but they belong in a separate total-cost-of-ownership question and they vary far more by model than by fuel type.
Use the petrol car's real economy, not its official figure. Comparing an honest EV number against an optimistic petrol number flatters the EV and tells you nothing useful.
Charging from your own roof is close to free at the margin, and it converts generation you would have exported cheaply into miles. That makes an EV one of the better companions to a solar array.
The catch is timing: generation peaks when many cars are at work. It works best for people at home during the day, or with a charger that can follow surplus generation.
