EV Charging Cost Calculator
Work out exactly what it costs to charge your EV from any percentage to any other.
Free calculator, no signup required. Runs in your browser — your entries stay on this device (saved in this browser until you clear them) and are not sent to us.
What a charge actually costs
The cost of charging an EV at home is the energy you draw from the wall multiplied by the price your utility charges per kilowatt-hour. Some of what comes from the wall does not end up in the battery. The U.S. Department of Energy and EPA note that charging losses vary with the equipment, conditions and vehicle (see fueleconomy.gov). This calculator divides the energy added to the battery by the wall-to-battery efficiency you enter to get the energy drawn from the wall.
Worked example (illustrative assumptions)
Assumptions: a 75 kWh battery, charging from 20% to 80%, 90% wall-to-battery efficiency, and an example rate of $0.15 per kWh. These are example inputs, not measured or current averages. The window adds 75 × 0.60 = 45 kWh to the battery. At 90% efficiency the wall supplies 45 ÷ 0.90 = 50 kWh, and 50 kWh × $0.15 = $7.50.
Battery-side energy (45 kWh) is what the pack receives; wall-side energy (50 kWh) is what the meter counts and what you pay for. Use the rate on your own bill, and note that fixed fees and session fees are not included.
Where you charge matters
- Home: priced by your utility tariff, which may vary by time of day. Use the rate on your bill.
- Public Level 2 and DC fast charging: priced by the network or host and shown in its app or on the charger. Pricing models differ (per kWh, per minute, session fees).
Efficiency is not a constant. Charging losses depend on the charger, vehicle and conditions (source: DOE/EPA fueleconomy.gov, Electric Vehicles, read October 15, 2026). The inputs must be: battery above 0 and up to 500 kWh, charge levels from 0 to 100% with the target above the start, and efficiency above 0% and up to 100%.
Frequently asked
How is the charging cost calculated?
Cost = battery capacity × percentage added, divided by charging efficiency, multiplied by your electricity rate. A 75 kWh battery going from 20% to 80% adds 45 kWh to the pack; with a 90% efficient charger, the wall draws about 50 kWh; at $0.15/kWh that is $7.50.
Why does the calculator factor in charging efficiency?
Some of the energy drawn from the wall does not reach the battery. The U.S. Department of Energy and EPA (fueleconomy.gov) explain that charging losses vary with the charging equipment, conditions and vehicle. This calculator takes your wall-to-battery efficiency, so the wall energy it shows is the figure your utility bill would count. The default of 90% is an example, not a measured value for your car.
What charging efficiency should I use?
Use a figure you can support. If you know how much energy your charger or car reports delivering to the battery versus how much your meter or charger recorded drawing from the wall, divide the first by the second. If you do not, keep the 90% example and treat the result as an estimate. Efficiency must be above 0% and at most 100%. Cold weather and other conditions can lower it.
Can I use this for public Level 2 or DC fast charging?
Yes. Change the electricity rate to the per-kWh price shown by the public charger or its app. Some networks bill per minute or add session fees, which this calculator does not include unless you fold them into an effective per-kWh rate. Efficiency for public charging depends on the equipment and vehicle, so enter your own figure if you have one.
What is a typical electricity rate to use?
Use the per-kWh rate on your own utility bill, including any energy and delivery charges that scale with usage. The $0.15/kWh in the example is an illustrative number, not a current national average. If your utility offers a time-of-use plan, use the rate for the hours you actually charge.
Does the calculator save my numbers?
The math runs in your browser and nothing you type is sent to us. Your last entries are kept in this browser’s local storage until you clear this site’s data, so the calculator reopens with them.