EV Home Charging Cost Calculator
Estimate the monthly and per-mile cost of charging your electric car at home from your driving distance, efficiency and electric rate.
How it works
Battery kWh = miles ÷ efficiency · Drawn kWh = battery ÷ (1 − loss%) · Cost = drawn × rate
Home charging cost is simply the energy your battery needs divided by charging efficiency, times your rate. Dividing miles by your car’s miles-per-kWh gives the energy stored in the battery, but the wall meter records more than that because 5–15% is lost as heat in the charger and battery. Charging overnight on an off-peak or EV time-of-use rate is the single biggest lever on this number, often halving the per-mile cost.
Worked example
At 1000 miles a month and 3.5 mi/kWh the battery needs 285.7 kWh. With 10% charging loss the wall delivers 285.7 ÷ 0.90 = 317.5 kWh. At $0.17/kWh that is $53.98 a month, or about $0.054 per mile — well below the fuel cost of most gasoline cars.
Frequently asked questions
How is this different from a general EV charging cost calculator?
This one starts from your monthly driving distance and the car’s miles-per-kWh, and adds real-world charging losses, to give a monthly bill and a cost per mile — rather than the cost of a single fill from a battery percentage.
What efficiency should I use?
Most EVs average 3–4 miles per kWh; efficient small cars can exceed 4, while heavy trucks and SUVs or cold-weather, high-speed driving can drop below 3. Your car’s trip computer shows a lifetime mi/kWh or Wh/mi figure — divide 1000 by Wh/mi to get mi/kWh.
Why add a charging loss?
Not all the electricity from the wall reaches the battery; some is lost as heat in the onboard charger and cells, typically 5–15%. Ignoring it understates your bill because you pay the meter, not the battery.
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This calculator is for educational purposes. Double-check important results before acting on them.