EV vs gas cost calculator
Enter your driving and prices, see which car is cheaper to fuel.
EPA label figures already include charging losses — leave 0 for them.
How do I compare the cost of an EV and a gas car?
Work out the fuel cost per mile of each. Gas car: price per gallon ÷ mpg. EV: price per kWh × kWh per 100 miles ÷ 100. Multiply by the miles you drive in a year, then by the years you plan to keep the car.
Example
12,000 miles a year. A 30 mpg car with gas at $3.50 costs $3.50 ÷ 30 = 11.7¢ a mile, $1,400 a year. An EV using 30 kWh per 100 miles at 17¢ per kWh costs 5.1¢ a mile, $612 a year. The EV saves $788 a year, so a $5,000 higher price takes about 6.3 years of fuel savings to pay back.
Should I add charging losses?
Not if you use the EPA label numbers: fueleconomy.gov says the MPGe and kWh per 100 miles on the label already include losses during charging. If your figure is energy taken from the battery, add them — fueleconomy.gov puts battery charging efficiency often at 84% to 93%, that is 7% to 16% lost.
How much CO₂ does each car cause?
The EPA says a gallon of gasoline produces 8,887 grams of CO₂ at the tailpipe. An EV’s share depends on how your electricity is made: look up your region’s CO₂ output rate in pounds per MWh in EPA’s eGRID data (its Power Profiler finds it by ZIP code) and enter it. The US average in eGRID2023 was 767 lb per MWh.
What is not included?
Only energy costs are compared. Purchase price is counted only through the price difference you enter; tax credits, maintenance, insurance, registration fees and higher public fast-charging prices are left out.
At what gas price does the EV stop saving money?
When a gallon costs no more than your mpg times the EV’s cost per mile. In the example above the EV costs 5.1¢ a mile, so a 30 mpg car matches it at $1.53 a gallon; gas above that price makes the EV cheaper to run. The comparison also depends on the electricity price: the same EV charged at 40¢ per kWh, as at some public fast chargers, costs 12.0¢ a mile and saves only $-40 a year.
What is MPGe?
Miles per gallon of gasoline-equivalent: the EPA counts 33.7 kWh of electricity as the energy of one gallon of gasoline. An EV using 30 kWh per 100 miles is rated 112 MPGe. MPGe compares energy used, not cost, so a car with a higher MPGe can still cost more per mile if your electricity is expensive.
The arithmetic behind the comparison
For each car the calculator finds fuel cost per mile, then yearly cost = miles × cost per mile. Gas car: price per gallon ÷ mpg. EV: price per kWh × kWh per 100 miles ÷ 100, where the kWh figure is raised by the charging loss if you enter one. The yearly saving is gas cost minus electricity cost; multiplying by the years you keep the car gives the total, and the extra purchase price of the EV divided by the yearly saving gives the payback time in years. Only energy cost is compared, so the result is a running-cost difference, not a total cost of ownership.
Worked example: 12,000 miles a year for 8 years
A 30 mpg car with gas at $3.50 costs $0.117 a mile, or $1,400 a year. An EV using 30 kWh per 100 miles at 17 cents per kWh costs $0.051 a mile, or $612 a year, so it saves $788 a year and $6,304 over 8 years. A $5,000 higher purchase price is recovered in 6.3 years, leaving $1,304 ahead after 8 years. If you add a 10% charging loss, the EV’s yearly cost rises to $680.
Common mistakes
Adding charging losses twice is the first: the EPA label figure in kWh per 100 miles already counts them, so enter a loss percentage only when your number is measured at the battery. The second is using one electricity price for everything; home charging at your utility rate and public fast charging can differ by a large factor, so weight the price by where you will actually charge. Also remember that tax credits, insurance, maintenance, registration fees and resale value are not in the calculation, so a short payback here is not a full cost comparison.
Sources: US EPA, Greenhouse Gas Emissions from a Typical Passenger Vehicle (8,887 g CO₂ per gallon of gasoline); fueleconomy.gov (DOE and EPA), Download Fuel Economy Data and All-Electric Vehicles; EPA eGRID2023 summary data. How we check our calculators.
Sources: fueleconomy.gov (U.S. Department of Energy and EPA) for the 33.7 kWh per gallon equivalence behind MPGe and for charging efficiency; EPA for the CO₂ per gallon figure. Related: EV charging calculator, MPGe calculator, fuel cost calculator and electricity cost calculator.