How it works
An electric car's running cost comes down to how much electricity it needs to cover your miles, plus the energy lost while charging, multiplied by what you pay per kWh. Efficient sedans such as a Tesla Model 3 use about 0.25 kWh per mile; big SUVs and pickups use 0.35 to 0.45.
Not all of the electricity from the wall reaches the battery: the charger and battery lose some as heat. On a Level 2 home charger that loss is typically around 10%; on a standard 120 V outlet it is often 15% or more. The calculator adds this back so the cost matches what your meter records.
If you charge partly at public fast chargers, set the share; those usually cost two to three times more per kWh than charging at home.
The formula
battery kWh = distance × kWh per mile (or km) kWh from wall = battery kWh ÷ (1 − charging loss) cost = kWh from wall × price per kWh cost per mile = cost ÷ distance
Worked example
A Tesla Model 3 (about 0.25 kWh per mile) driving 1,000 miles a month, charged at home at the US average of 18.2¢ per kWh with 10% charging loss.
| Step | Working | Result |
|---|---|---|
| Energy into the battery | 1,000 mi × 0.25 kWh | 250 kWh |
| Energy from the wall | 250 ÷ 0.9 | 277.8 kWh |
| Monthly cost at home | 277.8 × $0.182 | $50.56 |
| Cost per mile | $50.56 ÷ 1,000 | 5.1¢ |
| Same miles on DC fast chargers | 277.8 × $0.48 | $133.33 |
| One full 75 kWh charge at home | 75 ÷ 0.9 × $0.182 | $15.17 |
For comparison, a petrol car doing 30 miles per gallon needs about 33 gallons for the same 1,000 miles, which costs roughly $100 at $3 a gallon.
Frequently asked questions
How much does it cost to charge an electric car at home?
A typical EV uses 0.25 to 0.35 kWh per mile, so at the US average of 18.2¢ per kWh, plus about 10% charging loss, home charging costs roughly 5.1¢ to 7.1¢ a mile. A 1,000-mile month in an efficient sedan costs about $51.
How much does it cost to fully charge a Tesla?
A Model 3 or Model Y with a battery of about 75 kWh costs about $15.17 to charge from empty at 18.2¢ per kWh, allowing for 10% loss. Most people charge from about 20% to 80%, which costs well under half that. See our guide to charging a Tesla at home.
Is charging at home cheaper than public charging?
Usually much cheaper. US DC fast charging typically costs $0.45 to $0.50 per kWh, two to three times the average home price. In the UK, an off-peak EV tariff around 8p per kWh against about 54p at public chargers makes the gap even bigger.
How much electricity is lost when charging an EV?
Typically around 10% on a Level 2 (240 V) home charger, and 15% or more on a standard 120 V outlet, especially in cold weather when the battery is warmed during charging.
Should I use an EV tariff or time-of-use rate?
If your utility or supplier offers a cheap overnight rate, it is almost always worth scheduling charging into it. Enter the off-peak price as your home price to see the saving.
Sources
- Vehicle efficiency: US EPA ratings via fueleconomy.gov (Model 3 about 25 kWh per 100 miles).
- Home prices: US average residential price, EIA 2026 forecast (checked Oct 2026); Ofgem price cap unit rate, 1 Oct – 31 Dec 2026, Direct Debit (VAT on electricity is 0% until 31 Mar 2027).
- Public charging: Typical US DC fast charging, about $0.45–0.50 per kWh (Tesla Superchargers often $0.30–0.45); Average public charging price for slow and fast chargers (Octopus, Feb 2026); rapid chargers cost more.
- US Department of Energy, charging plug-in electric vehicles at home.
Related guides
Estimates are for planning only and are not financial advice. Get written quotes before you buy.