Cost per mile, which is the only comparable number
Two inputs: how far your car travels per kilowatt-hour, and what a kilowatt-hour costs you. Divide the first into the second and you have cents per mile.
At the US average of 18.34¢/kWh, including about 10% charging loss. Divide your own rate by your own miles per kWh to get your figure.
| Efficiency | Typical of | Cents per mile | 10,000 miles |
|---|---|---|---|
| 4.5 mi/kWh | An efficient compact EV in mild weather | 4.5¢ | $453 |
| 3.5 mi/kWh | A mainstream sedan or small crossover | 5.8¢ | $582 |
| 2.8 mi/kWh | A large SUV, or winter driving | 7.3¢ | $728 |
| 2 mi/kWh | An electric pickup, or towing | 10.2¢ | $1,019 |
For comparison, a petrol car doing 30 mpg at $3.60 a gallon costs 12 cents a mile. A mainstream EV at the US average electricity rate is around half that, and on an overnight tariff it can be a quarter or less. In Hawaii, at over 50 cents a kilowatt-hour, the two are close to level.
Level 1 and Level 2 cost almost the same
Both for the same 11,100 miles a year. The energy is nearly identical; only the time differs.
| Electricity a year | Cost a year | Hours to add 40 miles | |
|---|---|---|---|
| Level 1 — standard outlet | 3,747 kWh | $687 | About 11 |
| Level 2 — 240 V charger | 3,541 kWh | $649 | About 1.6 |
The tariff decision is worth more than the charger
Almost every US utility offers an EV or whole-home time-of-use rate that prices overnight electricity at a steep discount. Because charging is entirely shiftable — the car does not care when it charges, only that it is ready by morning — this is close to free money, and it is a larger saving than any equipment choice.
3,541 kWh a year, priced at various overnight rates. Set the car’s departure time once and this is permanent.
| If your overnight rate is | Charging a year | Saved against the average |
|---|---|---|
| 18.34¢/kWh | $649 | — |
| 14¢/kWh | $496 | $154 |
| 10¢/kWh | $354 | $295 |
| 7¢/kWh | $248 | $402 |
Home against public charging
The gap is wide enough to change what a car costs to own, and it is the main reason home charging matters more than charger choice.
Public rates vary widely by network and region; those are representative rather than quoted. A petrol car at 30 mpg and $3.60 a gallon is 12 cents a mile for comparison.
| Where you charge | Per kWh | Per mile at 3.5 mi/kWh | 10,000 miles |
|---|---|---|---|
| Home, overnight tariff | 11¢ | 3.5¢ | $349 |
| Home, average residential rate | 18¢ | 5.8¢ | $582 |
| Public Level 2 | 30¢ | 9.5¢ | $952 |
| DC fast charging | 48¢ | 15.2¢ | $1,524 |
A driver who relies on fast charging is paying close to petrol prices, and sometimes above them. Almost the whole financial case for an electric car assumes charging at home, which is worth knowing before buying one into a situation where that is not possible.
Do you actually need Level 2?
The honest answer for many drivers is no, and the calculation is straightforward. Level 1 on a standard outlet adds roughly 3 to 4 miles of range per hour. Over a twelve-hour overnight period that is 36 to 48 miles — more than the average US driver covers in a day.
- Under about 40 miles a day: Level 1 is genuinely sufficient, needs no electrician and no equipment beyond the cable in the boot.
- 40 to 80 miles a day: Level 1 works but leaves no margin. A cold snap or an unplanned trip means arriving at the weekend low.
- Over 80 miles a day, or two EVs: Level 2 is necessary rather than a convenience.
Where Level 2 does pay for itself is on a tariff with a narrow off-peak window. If cheap electricity is only available between midnight and six, a Level 1 charger cannot deliver a full day of range inside it — and there the faster charger is buying you the tariff, not the speed.
What people forget to count
- Charging losses. Roughly 10% at Level 2 and a little more at Level 1. The meter records what came out of the wall, not what went into the battery, so the figure on your bill is always higher than the car reports.
- Battery conditioning. In cold weather the car heats the pack before and during charging. Winter cost per mile is commonly 20–40% above summer, and none of it is visible in the car’s efficiency display.
- Preconditioning the cabin. Warming the car while plugged in is drawn from the wall, not the battery. It is the right thing to do for range, and it is electricity you pay for.
- The charger itself idling. A networked wall unit draws a few watts around the clock — small, but it is 8,760 hours a year.
What the installation costs, and when it is not needed
A Level 2 install is an electrician running a 240 V circuit from the panel to wherever the car sits, plus the unit itself. The cost is dominated by distance and by whether the panel has capacity — a garage attached to the panel wall is a straightforward job; a detached garage across a driveway is a different order of expense.
The panel question catches people out. An older 100 A service may not have room for a 40 or 50 A circuit without a load calculation, and the answer can be a service upgrade costing several times the charger. Two things avoid it: a charger with load management, which throttles the car when the rest of the house is drawing heavily, or simply charging at a lower amperage — which, as the table above shows, costs almost nothing in efficiency.
Against those, the arithmetic still comes out clearly in favour. Even at $649 a year with every loss counted, home charging is roughly half the fuel cost of an equivalent petrol car — and unlike petrol, the price is one you can partly choose by moving it overnight.
Questions
How much does it cost to charge an electric car at home?
Is it cheaper to charge slowly on a normal outlet?
Should I switch to an EV tariff?
Why is my winter charging cost higher?
All guides · How the figures are computed · Break down your own bill