EV vs gas cost calculator
Compare the yearly energy cost of a gas car and an electric car on your own miles, prices and efficiency.
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Yearly saving with the EV
USD per year
- Saving per month
- $
- Gas car, energy per year
- $
- Electric car, energy per year
- $
- Gas car, per mile
- $
- Electric car, per mile
- $
Energy cost only. A negative number means the EV costs more to run.
How this is calculated
Cost per mile for the gas car is the gas price divided by its mpg. For the electric car it is its kWh per 100 miles divided by 100, times the electricity price. Each is multiplied by your yearly miles, and the saving is the gas cost minus the electric cost. A negative saving means the EV costs more to run. If you give MPGe instead of kWh per 100 miles, it is converted first.
kWh per 100 miles = 3,370 ÷ MPGe
The method, the constants and the limits are written out in how fuel cost is calculated.
Where the 33.7 comes from
MPGe compares the energy in a gallon of gasoline with the energy an electric car uses. The convention is that one gallon of gasoline holds the same energy as 33.7 kWh of electricity. The U.S. Department of Energy’s fueleconomy.gov uses that figure, and AAA explains it in what MPGe is and how it is derived. A car that goes 100 miles on 33.7 kWh is rated 100 MPGe, so kWh per 100 miles is 3,370 divided by MPGe.
Worked example with hypothetical numbers
12,000 miles a year. Gas car: 30 mpg with gas at $3.50 a gallon. Electric car: 120 MPGe with electricity at $0.16 per kWh. These are made-up numbers.
- Gas: $3.50 ÷ 30 = $0.117 a mile, so 12,000 × that = $1,400.00 a year.
- EV energy: 3,370 ÷ 120 = 28.08 kWh per 100 miles. 28.08 ÷ 100 × $0.16 = $0.045 a mile, so $539.20 a year.
- Saving: $1,400.00 − $539.20 = $860.80 a year, or $71.73 a month.
What this leaves out
Only the cost of energy is compared. The purchase price, financing, insurance, maintenance, tires, registration fees, home charger installation and resale value are not in the result. Public fast charging usually costs more per kWh than charging at home, so if you rely on it, enter a price that reflects your real mix. Cold weather, speed and charging losses change how much energy a car uses, and your own figures may differ from a rating.
To see the cost of single charges, use the EV charging cost calculator. For the all-in cost per mile of either car, there is the cost per mile calculator. To work out the mpg of the gas car from a fill-up, use the fuel consumption calculator, or see the fuel cost calculator for a single trip.
Common questions
Which should I enter, kWh per 100 miles or MPGe?
Either. Use whichever your car’s rating or dashboard shows. If you enter MPGe, the tool converts it to kWh per 100 miles using 33.7 kWh per gallon-equivalent.
Why are there no preset prices?
Gas and electricity prices vary a lot by place and time, and a preset would be a guess. Enter the prices you actually pay.
What does a negative saving mean?
On the numbers you entered, the electric car costs more to run than the gas car.
Does the comparison include the cost of buying the car?
No. It compares the cost of energy only.