The strongest argument for an electric car is the fuel bill. A kilowatt-hour costs a fraction of the gasoline with the same energy, and electric motors waste much less of it. But the answer depends on your local prices, how you charge and how far you drive. This calculator compares a gasoline car and an EV on the same yearly mileage and shows the yearly saving, the saving over the years you plan to keep the car and, if you enter the price difference, the years it takes to recover it.
How to use the EV vs gas calculator
- Enter your yearly mileage. The US average is around 12,000–13,500 miles for a driver; use your own odometer figures if you have them.
- Enter the gas car’s mpg and the local gas price. Real-world mpg is more useful than the brochure figure.
- Enter the EV’s consumption in kWh per 100 miles (the EPA label shows it for each model) and the electricity price you will actually pay, blending home and public charging if you use both.
- Add the years of ownership and, optionally, the extra purchase price of the EV after incentives.
For the cost of a single charge see the EV charging cost calculator; to translate mpg into other units, use the fuel economy converter.
EV vs gas cost formula
EV cost per year = miles × kWh per 100 mi ÷ 100 × electricity price
Yearly saving = gas cost − EV cost
Break-even (years) = price premium ÷ yearly saving
The comparison holds everything else equal, which makes the answer easy to check. One useful shortcut is the cost per mile: gas price ÷ mpg for the gas car, and consumption × price ÷ 100 for the EV. At 30 mpg and $3.50 the gas car costs 11.7 cents per mile; an EV using 30 kWh per 100 miles at $0.17 costs 5.1 cents.
Worked example
You drive 12,000 miles a year. The gas car gets 30 mpg and gas is $3.50. The EV uses 30 kWh per 100 miles and electricity is $0.17 per kWh. You plan to keep the car for 5 years.
- Gas: 12,000 ÷ 30 = 400 gallons × $3.50 = $1,400 per year.
- EV: 12,000 × 0.30 = 3,600 kWh × $0.17 = $612 per year.
- Yearly saving: 1,400 − 612 = $788.
- Over 5 years: 788 × 5 = $3,940.
- If the EV costs $4,000 more to buy, it takes 4,000 ÷ 788 = 5.1 years for the fuel savings to make up the difference.
Yearly saving at different gas and electricity prices
Computed for 12,000 miles a year, a 30 mpg gas car and an EV using 30 kWh per 100 miles. A negative number would mean the EV costs more to fuel.
| Gas price per gallon | EV at $0.12/kWh | EV at $0.17/kWh | EV at $0.30/kWh |
|---|---|---|---|
| $3.00 | $768 | $588 | $120 |
| $3.50 | $968 | $788 | $320 |
| $4.00 | $1,168 | $988 | $520 |
| $4.50 | $1,368 | $1,188 | $720 |
What this comparison leaves out
Fuel is only one part of ownership. EVs typically cost more to buy, although tax credits, rebates and falling battery prices have narrowed the gap, and they avoid oil changes and many engine-related repairs. On the other hand, insurance can be higher, and installing a home charger costs a few hundred to a couple of thousand dollars. Depreciation depends on the model and the market. Weather also matters: cold temperatures reduce an EV’s efficiency, and highway driving uses more energy per mile than city driving.
Where you charge changes the answer more than almost anything else. At a home rate of $0.15 per kWh the EV is dramatically cheaper than gas; if you must rely on public fast charging at $0.45 per kWh, the fuel cost per mile approaches that of an efficient hybrid. Run the calculator with both prices to see the range of outcomes before you decide.
Sources
The 33.7 kWh-per-gallon-equivalent convention and the per-model kWh per 100 miles figures come from the US EPA and Department of Energy at fueleconomy.gov. Gas and electricity prices should be taken from your own bill and local station prices; national averages are published by the US Energy Information Administration (eia.gov).
Frequently asked questions
Is an electric car cheaper to run than a gas car?
Usually, yes. With gas at $3.50 per gallon, a 30 mpg car and an EV using 30 kWh per 100 miles at $0.17 per kWh, the EV’s fuel costs about 5 cents per mile against 12 cents. If you rely on expensive public fast charging, the gap can disappear.
What is MPGe and how does it relate to kWh per 100 miles?
MPGe treats 33.7 kWh of electricity as equal to one gallon of gasoline. Divide 3,370 by the kWh/100 mi figure to get MPGe — for example 30 kWh per 100 miles is about 112 MPGe. MPGe compares energy, not cost, which is why this calculator uses actual prices.
Does this include maintenance, insurance or depreciation?
No — only fuel and electricity. EVs generally need less routine maintenance (no oil changes), but insurance, tires and depreciation vary by model. Use the premium box only for the extra purchase price.
How do I handle a mix of home and public charging?
Use a weighted average price. If 80% of your energy is $0.15 home power and 20% is $0.45 public fast charging, the blended price is 0.8 × 0.15 + 0.2 × 0.45 = $0.21 per kWh.
What if I drive an EV and a plug-in hybrid?
This calculator compares a full EV with a gasoline-only car. A plug-in hybrid uses both fuels in proportion to how far it runs on electricity, so it needs a weighted calculation.