Answer first
What this calculator tells you
Estimate monthly charging cost and cost per mile for an electric vehicle at home rates. Compare the monthly charging cost with what you spend on gasoline today. Formula: kWh from the wall = miles ÷ 100 × kWh per 100 miles ÷ (1 − charging loss); cost = kWh × price. At the worked-example inputs, the charging cost per month is $57. Holding every other input steady, moving electricity price per kwh from $0.14 to $0.20 moves the result from $47 to $67.
Transparent method
The formula
Compare the monthly charging cost with what you spend on gasoline today.
Worked example
Example inputs
How to interpret the result
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.
At the worked-example inputs the charging cost per month is $57. It rises with electricity price per kwh, vehicle efficiency (kwh per 100 miles), miles driven per month and charging loss.
Real energy use depends on how the appliance or vehicle is actually run: duty cycle, weather, driving style, battery age and your utility's rate structure, including tiers and time-of-use pricing. Treat the result as a planning estimate and check it against your own bill or trip log.
Before you rely on it
What to check
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.
The common error
Where people go wrong with EV charging cost calculator
Ignoring charging loss. The wall draws more than the battery stores, so leaving the loss at zero understates the monthly bill.
Sensitivity evidence
How electricity price per kwh changes the charging cost per month
Holding every other input at the worked-example value, moving electricity price per kwh from $0.14 to $0.20 moves the charging cost per month from $47 to $67: a spread of $20, or 35% of the worked-example result.
| Electricity price per kWh | Charging cost per month | Cost per mile | Energy drawn from the wall (kWh) |
|---|---|---|---|
| $0.14 | $47 | $0.05 | 333.3 |
| $0.15 | $50 | $0.05 | 333.3 |
| $0.17worked example | $57 | $0.06 | 333.3 |
| $0.19 | $63 | $0.06 | 333.3 |
| $0.20 | $67 | $0.07 | 333.3 |
Every input, tested
Which input moves the charging cost per month most
Of the 4 inputs, electricity price per kwh moves the charging cost per month most ($13 across the range tested) and charging loss moves it least ($2.52).
| Input | Tested from | To | Charging cost per month at each end | Swing |
|---|---|---|---|---|
| Electricity price per kWh | $0.15 | $0.19 | $50 to $63 | $13 (24%) |
| Vehicle efficiency (kWh per 100 miles) | 27 | 33 | $51 to $62 | $11 (20%) |
| Miles driven per month | 900 | 1,100 | $51 to $62 | $11 (20%) |
| Charging loss | 8.0% | 12.0% | $55 to $58 | $2.52 (4.4%) |
Two variables at once
Charging cost per month by electricity price per kwh and vehicle efficiency (kwh per 100 miles)
Across the grid the charging cost per month runs from $37 to $80. Moving electricity price per kwh from $0.14 to $0.20 shifts it by $20 at the middle column, and moving vehicle efficiency (kwh per 100 miles) from 24 to 36 shifts it by $23 at the middle row, so vehicle efficiency (kwh per 100 miles) is the bigger lever here.
| Electricity price per kWh \ Vehicle efficiency (kWh per 100 miles) | 24 | 30 | 36 |
|---|---|---|---|
| $0.14 | $37 | $47 | $56 |
| $0.15 | $40 | $50 | $60 |
| $0.17 | $45 | $57 | $68 |
| $0.19 | $51 | $63 | $76 |
| $0.20 | $53 | $67 | $80 |
The highlighted cell is the worked example: $57.
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Vehicle efficiency (kWh per 100 miles) | 30 | On the window sticker or at fueleconomy.gov for your model. |
| Miles driven per month | 1,000 | Enter the miles driven per month used in this calculation. |
| Electricity price per kWh | $0.17 | Found on your bill, in dollars per kilowatt-hour. |
| Charging loss | 10.0% | Energy lost as heat between the wall and the battery. Home charging usually loses 10 to 15 percent. |
| Charging cost per month | $57 | |
| Cost per mile | $0.06 | |
| Energy drawn from the wall (kWh) | 333.3 | |
Inputs, definitions and assumptions
Vehicle efficiency (kWh per 100 miles)
On the window sticker or at fueleconomy.gov for your model. The prefilled worked-example value is 30.
Miles driven per month
Enter the miles driven per month used in this calculation. The prefilled worked-example value is 1,000.
Electricity price per kWh
Found on your bill, in dollars per kilowatt-hour. The prefilled worked-example value is $0.17.
Charging loss
Energy lost as heat between the wall and the battery. Home charging usually loses 10 to 15 percent. The prefilled worked-example value is 10.0%.
How to use this calculator
- 1Verify the inputs. Gather vehicle efficiency (kwh per 100 miles), miles driven per month, electricity price per kwh and charging loss from your own documents; the prefilled values are examples.
- 2Save a baseline. The worked example puts the charging cost per month at $57. Store your own version of it as Scenario A.
- 3Test one change. Start with electricity price per kwh, the input with the biggest effect here: moving electricity price per kwh from $0.15 to $0.19 takes the charging cost per month from $50 to $63, a swing of 24% of the worked-example figure.
- 4Check the extremes. At half the example electricity price per kwh ($0.09) the charging cost per month is $28; at double ($0.34) it is $113.
People also ask
Frequently asked questions
How do you calculate EV charging cost?
kWh from the wall = miles ÷ 100 × kWh per 100 miles ÷ (1 − charging loss); cost = kWh × price. Enter electricity price per kwh in dollars and charging loss in percent (10 means 10%). At the worked-example inputs the charging cost per month is $57.
What does the EV charging cost result mean?
Compare the monthly charging cost with what you spend on gasoline today. At the worked-example inputs the charging cost per month is $57. It rises with electricity price per kwh, vehicle efficiency (kwh per 100 miles), miles driven per month and charging loss.
How much does electricity price per kwh change the charging cost per month?
Holding every other input at the worked-example value, moving electricity price per kwh from $0.14 to $0.20 moves the charging cost per month from $47 to $67, a spread of $20.
What are the limits of this EV charging cost calculator?
Real energy use depends on how the appliance or vehicle is actually run: duty cycle, weather, driving style, battery age and your utility's rate structure, including tiers and time-of-use pricing. Treat the result as a planning estimate and check it against your own bill or trip log. The tables on this page test electricity price per kwh only from $0.14 to $0.20; a value outside that range is not tabulated here.
Which input moves the charging cost per month most in the EV charging cost calculator?
Ranked by how far each moves the charging cost per month across the range tested: electricity price per kwh ($13, 24%), vehicle efficiency (kwh per 100 miles) ($11, 20%), miles driven per month ($11, 20%) and charging loss ($2.52, 4.4%).
If I double electricity price per kwh in the EV charging cost calculator, does the charging cost per month double?
Doubling it from $0.17 to $0.34 takes the charging cost per month from $57 to $113, which is 2.00 times the worked-example figure. So the result scales almost exactly in proportion. Halving it to $0.09 gives $28.
How much does vehicle efficiency (kwh per 100 miles) matter in the EV charging cost calculator?
The worked example uses 30. Holding every other input at its worked-example value, moving vehicle efficiency (kwh per 100 miles) from 27 to 33 takes the charging cost per month from $51 to $62, a swing of 20% of the worked-example figure.
How much does miles driven per month matter in the EV charging cost calculator?
The worked example uses 1,000. Holding every other input at its worked-example value, moving miles driven per month from 900 to 1,100 takes the charging cost per month from $51 to $62, a swing of 20% of the worked-example figure.
How much does charging loss matter in the EV charging cost calculator?
The worked example uses 10.0%. Holding every other input at its worked-example value, moving charging loss from 8.0% to 12.0% takes the charging cost per month from $55 to $58, a swing of 4.4% of the worked-example figure.
Which inputs change the cost per mile in the EV charging cost calculator?
At the worked-example inputs it is $0.06. Vehicle efficiency (kwh per 100 miles) takes it from $0.05 to $0.06, electricity price per kwh takes it from $0.05 to $0.06 and charging loss takes it from $0.06 to $0.06.
Which inputs change the energy drawn from the wall (kwh) in the EV charging cost calculator?
At the worked-example inputs it is 333.3. Vehicle efficiency (kwh per 100 miles) takes it from 300 to 366.7, miles driven per month takes it from 300 to 366.7 and charging loss takes it from 326.1 to 340.9.
Do EV efficiency figures include charging losses?
It depends on how the figure was measured, so check the source. The EV calculator lets you add a loss percentage, so the cost reflects what the wall supplies and not only what reaches the battery.
How do I measure my real gas mileage?
Fill the tank, note the odometer, drive normally, then fill again. Miles since the first fill divided by the gallons added is your mileage for that tank. Average a few tanks.
Why do solar panels produce less than their rated watts?
Ratings come from lab conditions of strong sun and cool panels. Real roofs face heat, dirt, shade, wiring losses and an angled sun, so a planning loss of around 14 percent is a common allowance.
Sources and evidence
Free Calculators Online is independent and is not affiliated with or endorsed by the source organizations. Educational estimates only.