Calculate the cost to charge an EV at home or on public chargers, including cost per full charge, cost per mile, and monthly charging cost with losses included.
EV Charging Cost Formula
CC = BC * (SOC2 - SOC1)/100 / (CE/100) * P
DC = D * EC/100 / (CE/100) * P
- CC is the cost to charge the battery ($)
- BC is the battery capacity (kWh)
- SOC1 and SOC2 are the starting and ending state of charge (%)
- CE is the charging efficiency (%), typically 85 to 95
- P is the electricity price ($/kWh)
- DC is the cost to drive a distance ($)
- D is the distance driven (miles)
- EC is the vehicle efficiency (kWh/100 miles)
The calculator has three modes built on these formulas. The charging cost mode uses the first formula: it takes the battery capacity, the portion of the battery you are filling, and the price per kWh, then divides by charging efficiency because the meter bills you for energy lost as heat during charging, not just the energy that ends up in the pack. The distance mode uses the second formula to price a specific trip from your vehicle's efficiency rating, and reports cost per mile and per 100 miles. The monthly mode extends the distance formula across your monthly mileage and splits the energy between a home rate and a public rate based on how much of your charging happens at home.
Typical Charging Prices by Location
Where you plug in matters more than any other factor. The table below shows typical US prices in 2026 and what they mean per 100 miles for an EV that uses 28 kWh per 100 miles, including a 10% charging loss.
| Charging location | Typical price per kWh | Cost per 100 miles |
|---|---|---|
| Home, standard rate | $0.17 | $5.29 |
| Home, off-peak TOU plan | $0.10 to $0.13 | $3.11 to $4.04 |
| Public Level 2 | $0.25 to $0.40 | $7.78 to $12.44 |
| DC fast charger | $0.45 to $0.50 | $14.00 to $15.56 |
Most charging-cost estimates multiply battery size by price and stop there. That undercounts your bill, because 5 to 15% of the energy you pay for never reaches the battery. It is lost as heat in the onboard charger, the cabling, and battery conditioning. The table below shows what that loss looks like on your bill at a $0.17/kWh home rate with a typical 90% efficient AC charge.
| Energy added to battery | Energy billed by the meter | Hidden loss cost |
|---|---|---|
| 40 kWh | 44.4 kWh | $0.76 |
| 60 kWh | 66.7 kWh | $1.13 |
| 80 kWh | 88.9 kWh | $1.51 |
| 100 kWh | 111.1 kWh | $1.89 |
Level 1 charging from a standard wall outlet runs closer to 80 to 85% efficient, so trickle charging costs slightly more per mile than a Level 2 unit on the same rate.
Example Problems
Example 1: Charging at home. You have an EV with a 75 kWh battery, you charge from 20% to 80% at a home rate of $0.17/kWh, and charging efficiency is 90%. The energy added to the battery is 75 * (80 - 20)/100 = 45 kWh. The energy billed from the grid is 45 / 0.90 = 50 kWh. The cost is 50 * $0.17 = $8.50. A full 0 to 100% charge would cost 75 / 0.90 * $0.17 = $14.17.
Example 2: A road trip on fast chargers. You plan a 500 mile trip in an EV that uses 28 kWh per 100 miles, charging only at DC fast chargers priced at $0.48/kWh with 90% efficiency. The car needs 500 * 28/100 = 140 kWh, which requires 140 / 0.90 = 155.6 kWh billed. The trip costs 155.6 * $0.48 = $74.67, or about $0.149 per mile ($14.93 per 100 miles).
FAQ
Why is my real charging cost higher than battery size times price? Because of charging losses. The onboard charger converts AC power to DC and loses energy as heat, and the car spends some energy running pumps, fans, and battery conditioning during the charge. Your utility meter records everything drawn from the wall, so you pay for the lost energy too. Losses typically run 5 to 15%, and they are worst on slow Level 1 charging in cold weather. This calculator divides by charging efficiency so the estimate matches what the meter actually records.
Is DC fast charging worth the higher price? Fast charging buys time, not savings. At around $0.48/kWh it costs roughly three times the average home rate, and for many EVs it approaches the per-mile fuel cost of an efficient gas car. It makes sense on road trips and in a pinch, but drivers who do most charging at home, especially on an off-peak overnight plan, pay a fraction as much per mile. If you rely on public charging full time, check whether network membership plans or workplace charging can bring your average rate down.
How much will an EV add to my monthly electric bill? Take your monthly miles, multiply by your car's kWh per mile, divide by charging efficiency, then multiply by your rate. A typical driver covering 1,100 miles per month in an EV that uses 28 kWh per 100 miles draws about 342 kWh from the grid at 90% efficiency, which is roughly $58 per month at $0.17/kWh. On a $0.12 overnight TOU rate the same driving costs about $41.
