Key takeaways
- Cost = grid energy × your $/kWh rate, where grid energy includes charging losses.
- Charging a 75 kWh EV from 20% to 80% adds 45 kWh and costs about $8.50 at $0.17/kWh.
- Charging efficiency means you pay for more than reaches the battery — 45 kWh added draws ~50 kWh from the grid.
- At 3.5 mi/kWh that charge adds 157.5 miles for roughly $0.054 per mile.
How to calculate EV charging cost
The cost to charge an EV comes down to three things: how much energy you add to the battery, how much extra the grid supplies because of charging losses, and what your utility charges per kilowatt-hour. Energy added is the battery size times the change in state of charge; cost is the grid energy times your rate.
Charging efficiency matters because you are billed for every kilowatt-hour that leaves the wall, not just the portion landing in the battery. At 90% efficiency, a 45 kWh top-up pulls about 50 kWh from the grid.
Worked example: 20% → 80% on a 75 kWh battery
Energy added = 75 × (80 − 20) ÷ 100 = 45 kWh. Grid energy = 45 ÷ 0.90 = 50 kWh. Cost = 50 × $0.17 = $8.50. Miles added = 45 × 3.5 = 157.5 miles, so cost per mile = $8.50 ÷ 157.5 ≈ $0.054. A full 0–100% charge would draw 75 ÷ 0.90 = 83.3 kWh and cost about $14.17.
Cost to charge 20% → 80% by electricity rate (75 kWh battery)
| Electricity rate | Grid energy | Cost to charge |
|---|---|---|
| $0.10 / kWh | 50 kWh | $5.00 |
| $0.15 / kWh | 50 kWh | $7.50 |
| $0.20 / kWh | 50 kWh | $10.00 |
| $0.30 / kWh | 50 kWh | $15.00 |
Comparing EV cost against gas
At about $0.054 per mile, a home-charged EV is usually far cheaper to run than a gasoline car near $0.10–$0.13 per mile. To compare the two in the same units, run your numbers through the cost per mile calculator.
Frequently asked questions
How much does it cost to charge an EV at home?
Multiply energy added (kWh) by your rate, divided by efficiency. A 75 kWh battery from 20%→80% adds 45 kWh; at 90% efficiency that's 50 kWh from the grid, so about $8.50 at $0.17/kWh.
Is charging an EV cheaper than buying gas?
Usually yes. At $0.17/kWh and 3.5 mi/kWh an EV runs ~$0.054/mile, versus ~$0.117/mile for a 30 mpg car at $3.50/gal — more than double.
What is charging efficiency and charging loss?
Some wall energy is lost as heat in the charger and cables. Home AC charging is ~85–90% efficient, so a 45 kWh top-up actually draws ~50 kWh — and you pay for all 50.
Does DC fast charging cost more than home charging?
Yes, often two to four times more. Public DC fast chargers commonly bill $0.30–$0.60/kWh plus possible session or idle fees, versus ~$0.16–$0.17 at home.
What is the cost per mile for an EV?
Cost per mile = cost to charge ÷ miles added. Adding 45 kWh for $8.50 at 3.5 mi/kWh gives 157.5 miles, or about $0.054 per mile.
How can I lower my EV charging cost?
Charge at home on an off-peak or EV time-of-use rate, avoid frequent DC fast charging, keep tires inflated, and precondition while still plugged in.
Home charging is billed at your utility's $/kWh rate, which varies by region and time of day; the US residential average is around $0.16–$0.17 per kWh — see the EIA average electricity price. Public DC fast charging is priced separately and is typically much higher.
Last reviewed June 2026