EV Charging Cost Calculator
Calculate what it costs to charge your electric vehicle for a given distance from its efficiency, your electricity rate, and charger efficiency losses.
How to use this tool
- Enter the distance you want to charge for, in miles.
- Enter your EV's efficiency in miles per kWh (from its trip computer).
- Enter the electricity rate at the charger, in dollars per kWh.
- Set the charging efficiency (about 0.90 for home Level 2).
- Read the grid energy used and the charging cost.
Find out what it costs to charge your electric car. Enter the distance, your EV's efficiency, your electricity rate, and charging losses to get the grid energy used and the dollar cost.
Formula
Energy that reaches the battery is distance divided by efficiency; grid energy is higher because of charging losses:
Battery energy (kWh) = Miles ÷ Efficiency (mi/kWh)
Grid energy = Battery energy ÷ Charging efficiency
Charging cost = Grid energy × Rate
How it works
The cost to charge an EV starts with how far you want to drive and how efficiently the car turns energy into miles. Dividing distance by efficiency (miles per kWh) gives the energy that must end up in the battery. But not all energy drawn from the wall reaches the battery — onboard chargers, cabling, and AC-to-DC conversion lose roughly 5–15%. Dividing battery energy by the charging efficiency grosses it up to the grid energy you actually pay for.
Multiplying grid energy by your electricity rate gives the charging cost. At home overnight rates this is usually a fraction of the gasoline cost for the same distance; at public DC fast chargers the per-kWh price is higher, which this tool captures simply by entering the higher rate.
Vehicle efficiency varies with speed, temperature, terrain, and climate-control use — cold weather can cut it by 20–30%. Use your car's observed mi/kWh from its trip computer for the most accurate result. The charging-efficiency input lets you model Level 1, Level 2, and DC fast charging, which have somewhat different loss profiles.
Worked example
100 miles, 4 mi/kWh, $0.15/kWh, 90% charging efficiency
- Battery energy = 100 mi ÷ 4 mi/kWh = 25 kWh.
- Grid energy = 25 kWh ÷ 0.90 = 27.78 kWh.
- Charging cost = 27.78 kWh × $0.15 = $4.17.
Grid energy 27.78 kWh | Charging cost $4.17
Charging cost per 100 miles (90% charging efficiency)
| Efficiency | At $0.10/kWh | At $0.15/kWh | At $0.20/kWh |
|---|---|---|---|
| 3.0 mi/kWh | $3.70 | $5.56 | $7.41 |
| 3.5 mi/kWh | $3.17 | $4.76 | $6.35 |
| 4.0 mi/kWh | $2.78 | $4.17 | $5.56 |
| 4.5 mi/kWh | $2.47 | $3.70 | $4.94 |
Key terms
- Efficiency (mi/kWh)
- How many miles an EV travels per kilowatt-hour of battery energy. Higher is better; most EVs manage 3–4.5 mi/kWh.
- Charging efficiency
- The fraction of energy drawn from the grid that actually reaches the battery, after charger and conversion losses — typically 85–95%.
- Grid energy
- The kWh metered at the wall or charger, which is what you are billed for — higher than the energy stored in the battery.
- kWh per 100 miles
- An alternative efficiency measure (the inverse of mi/kWh, scaled). The EPA reports EV efficiency this way as well as in MPGe.
Frequently asked questions
- How much does it cost to charge an EV at home?
- For a typical EV at 4 mi/kWh, 90% charging efficiency, and $0.15/kWh, about 100 miles of range costs roughly $4. Overnight off-peak rates make it cheaper; public DC fast charging at $0.30–0.50/kWh costs several times more.
- Why is grid energy higher than battery energy?
- Charging isn't perfectly efficient. Some energy is lost as heat in the onboard charger, cables, and AC-to-DC conversion, so you draw more from the grid than ends up stored — usually 5–15% more.
- Does cold weather increase charging cost?
- Yes. Cold reduces driving efficiency (more kWh per mile) and adds battery-conditioning and cabin-heating loads, so the same trip needs more energy. Lower the mi/kWh input to reflect winter driving.