Enter consumption in kWh per 100 miles, monthly miles and the marginal electricity price. Identify the consumption measurement first: EPA AC label consumption accounts for charging losses, so leave additional loss at zero. For battery-only consumption, enter a separately measured wall-to-battery loss; do not apply it twice.
EV Charging Cost: worked example
| Vehicle efficiency (kWh per 100 miles) | 30 |
|---|---|
| Miles driven per month | 1,000 |
| Electricity price per kWh | $0.17 |
| Additional charging loss | 0.000% |
| Charging cost per month | $51 |
| Cost per mile | $0.05 |
| Energy drawn from the wall (kWh) | 300 |
EV Charging Cost: changing Electricity price per kWh
| Electricity price per kWh | Charging cost per month | Cost per mile | Energy drawn from the wall (kWh) |
|---|---|---|---|
| $0.14 | $42 | $0.04 | 300 |
| $0.15 | $45 | $0.05 | 300 |
| $0.17 (example) | $51 | $0.05 | 300 |
| $0.19 | $57 | $0.06 | 300 |
| $0.20 | $60 | $0.06 | 300 |
EV Charging Cost: compare input ranges
| Input | Tested from | To | Charging cost per month: low input | Charging cost per month: high input | Swing |
|---|---|---|---|---|---|
| Electricity price per kWh | $0.15 | $0.19 | $45 | $57 | $12 (24%) |
| Vehicle efficiency (kWh per 100 miles) | 27 | 33 | $46 | $56 | $10 (20%) |
| Miles driven per month | 900 | 1,100 | $46 | $56 | $10 (20%) |
| Additional charging loss | -0.250% | 0.250% | $51 | $51 | $0.26 (0.5%) |
EV Charging Cost: individual input comparisons
| Input | Value | Charging cost per month | Cost per mile | Energy drawn from the wall (kWh) |
|---|---|---|---|---|
| Vehicle efficiency (kWh per 100 miles) | 24 | $41 | $0.04 | 240 |
| 27 | $46 | $0.05 | 270 | |
| 30 | $51 | $0.05 | 300 | |
| 33 | $56 | $0.06 | 330 | |
| 36 | $61 | $0.06 | 360 | |
| Miles driven per month | 800 | $41 | $0.05 | 240 |
| 900 | $46 | $0.05 | 270 | |
| 1,000 | $51 | $0.05 | 300 | |
| 1,100 | $56 | $0.05 | 330 | |
| 1,200 | $61 | $0.05 | 360 | |
| Electricity price per kWh | $0.14 | $42 | $0.04 | 300 |
| $0.15 | $45 | $0.05 | 300 | |
| $0.17 | $51 | $0.05 | 300 | |
| $0.19 | $57 | $0.06 | 300 | |
| $0.20 | $60 | $0.06 | 300 | |
| Additional charging loss | -0.500% | $51 | $0.05 | 298.5 |
| -0.250% | $51 | $0.05 | 299.3 | |
| 0.000% | $51 | $0.05 | 300 | |
| 0.250% | $51 | $0.05 | 300.8 | |
| 0.500% | $51 | $0.05 | 301.5 |
EV Charging Cost: combined input changes
| Electricity price per kWh / Vehicle efficiency (kWh per 100 miles) | 24 | 30 | 36 |
|---|---|---|---|
| $0.14 | $34 | $42 | $50 |
| $0.15 | $36 | $45 | $54 |
| $0.17 | $41 | $51 | $61 |
| $0.19 | $46 | $57 | $68 |
| $0.20 | $48 | $60 | $72 |
EV Charging Cost: which assumptions move the result?
EV Charging Cost: values and definitions
| Quantity and definition | Value used |
|---|---|
| Vehicle efficiency (kWh per 100 miles) — If using an EPA wall-energy label value, set the additional charging loss to zero. Battery-only consumption needs a separate loss allowance. | 30 |
| Miles driven per month | 1,000 |
| Electricity price per kWh — Found on your bill, in dollars per kilowatt-hour. | $0.17 |
| Additional charging loss — Set zero for a value already measured at the wall. Use a measured loss only for battery-side consumption. | 0.000% |
| Charging cost per month | $51 |
| Cost per mile | $0.05 |
| Energy drawn from the wall (kWh) | 300 |
EV Charging Cost: half and double Electricity price per kWh
| Electricity price per kWh | Charging cost per month |
|---|---|
| $0.09 | $26 |
| $0.17 | $51 |
| $0.34 | $102 |
Rates, weather, speed and charging equipment affect cost. Use all applicable marginal energy charges, with any fixed subscription or session fee separate. The result excludes equipment installation, depreciation and maintenance; it is an electricity comparison, not total ownership cost.
EV Charging Cost: formula
FuelEconomy.gov: U.S. Department of Energy and EPA · EPA: EV testing
Common error: Ignoring charging loss. The wall draws more than the battery stores, so leaving the loss at zero understates the monthly bill.
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An electric car's efficiency is quoted at the battery, but you pay at the wall, and some energy is lost as heat in between. At 30 kWh per 100 miles with 10 percent loss, 1,000 miles draws about 333 kWh from the outlet. At 17 cents that is roughly $57 a month, or under six cents a mile.
Home rates and public fast charging can differ by a large margin.
Use your own utility rate, and check whether it changes by time of day. Overnight rates can make the result lower than a flat rate suggests.
Compare the cost with gasoline on the MPG calculator, see the cost of other appliances on the electricity cost calculator, and offset charging with the solar panel output calculator. The battery runtime and solar payback pages cover related energy questions.
Should I add a loss to the EPA kWh-per-100-miles label?
No. EPA explains that its AC charging measurement already accounts for charging equipment losses. Applying another charging-loss adjustment to that same wall-energy figure would count the loss twice and overstate the electricity purchased.
What rate belongs in the example?
The price for the charging hours and location you will use, rather than a universal home or public-charging average.
How much does it cost to charge an electric car at home?
Use wall-energy consumption per mile. Multiply by the applicable electricity price. Four-to-six cents is a scenario.
It is not a current U.S. price fact. Check whether the vehicle’s consumption figure already includes charging losses before adding an allowance; applying the same loss twice overstates purchased energy and the resulting cost per mile.
Why include a charging loss?
Some energy is lost as heat in the charger and battery, so the wall draws more than reaches the battery.
Is home charging cheaper than gas?
Compare both costs per mile from actual energy prices and efficiencies. Home charging is not automatically cheaper. Time-of-use periods, public charging fees, session charges and the vehicle’s consumption can change the comparison; use the same travel distance and avoid counting a charging loss twice.