Key takeaways
- EV cost/mi = electricity rate ($/kWh) ÷ efficiency (mi/kWh), then bumped up ~10% for charging losses.
- Gas cost/mi = fuel price ($/gal) ÷ MPG. Simpler, because there's no charging loss to account for.
- At typical numbers, home charging runs about $0.05–0.06/mi versus roughly $0.125/mi for a 28-MPG gas car.
- Home charging is the cheap case. Public DC fast charging costs much more and can sometimes approach gasoline's per-mile cost.
The two cost-per-mile formulas
Both fuels boil down to one fair comparison: dollars per mile. For gas it's almost trivial — divide the price of a gallon by how many miles that gallon takes you. For an EV it's the same idea, but you divide the price of a kilowatt-hour by how many miles that kWh takes you, then add a small penalty because some energy is lost as heat while charging.
That charging loss matters. When you pour 50 kWh from the wall into the car, only about 45 kWh lands in the battery — call it ~90% charging efficiency, a 10% tax on every kWh you pay for. Ignore it and you understate your EV cost by about a tenth.
So an EV at 3.5 mi/kWh on $0.17/kWh electricity costs 0.17 ÷ 3.5 = $0.0486/mi before losses, and 0.0486 ÷ 0.90 ≈ $0.054/mi once you account for them. The EV charging cost calculator handles the loss factor for you; for an apples-to-apples figure against any gas car, the cost per mile calculator compares both on the same basis.
EV vs gas at typical numbers
Here's how the per-mile math lands across efficient and thirsty examples. EV rows already include the ~10% charging-loss adjustment.
| Vehicle | Efficiency | Energy price | Cost per mile |
|---|---|---|---|
| EV (efficient) | 4.0 mi/kWh | $0.17/kWh | ≈ $0.047/mi |
| EV (typical) | 3.5 mi/kWh | $0.17/kWh | ≈ $0.054/mi |
| EV (thirsty SUV) | 2.5 mi/kWh | $0.17/kWh | ≈ $0.076/mi |
| Gas (efficient) | 40 MPG | $3.50/gal | ≈ $0.088/mi |
| Gas (typical) | 28 MPG | $3.50/gal | ≈ $0.125/mi |
| Gas (thirsty truck) | 18 MPG | $3.50/gal | ≈ $0.194/mi |
Even a thirsty EV at 2.5 mi/kWh undercuts a 28-MPG sedan, and an efficient EV costs barely a third of what a thirsty truck spends per mile. The gap widens wherever electricity is cheap or gas is expensive.
A worked example: 158 miles of driving
Take a 75 kWh EV charged at home from 20% to 80%. That's a 60% top-up, so you add about 45 kWh to the battery — but with ~90% charging efficiency you actually pull roughly 50 kWh from the grid. At $0.17/kWh that's about $8.50. At 3.5 mi/kWh, the 45 kWh in the battery covers about 158 miles, which works out to $0.054/mi.
Now drive the same 158 miles in a 28-MPG gas car. That burns about 5.6 gallons, and at $3.50/gal the fuel bill is about $19.70 — more than double the EV's $8.50 for the identical trip.
Home vs public fast charging
The numbers above assume home charging, which is where EVs shine. Level 1 and Level 2 charging in your driveway is billed at your normal residential rate — often $0.12–$0.20/kWh. Public DC fast charging is a different story: it's priced well above home rates, and at the highest public rates the cost per mile can climb toward — and occasionally past — what a gas car spends. If you mostly charge at home and only fast-charge on road trips, your blended cost stays close to the cheap end of these tables.
Frequently asked questions
Is an EV cheaper to drive than gas?
Almost always, when charging at home. A typical EV at 3.5 mi/kWh on $0.17/kWh costs about $0.05–0.06 per mile, versus about $0.125 per mile for a 28-MPG car on $3.50/gal gas — roughly half to a third of the per-mile fuel cost.
How much does it cost to charge an EV at home?
Multiply the kWh you add by your electricity rate, then add ~10% for charging losses. Charging a 75 kWh battery from 20% to 80% adds about 45 kWh, draws roughly 50 kWh from the grid, and at $0.17/kWh costs about $8.50 for around 158 miles.
Does fast charging cost more than home charging?
Yes. Public DC fast charging is priced well above home electricity rates and can sometimes approach the per-mile cost of gasoline. Home Level 1 or Level 2 charging is almost always the cheapest way to fuel an EV.