How to use the ev vs gas cost calculator
- Enter the miles driven per year and the years you will own the car.
- Enter the gas car's fuel economy and the gas price, then the EV's miles per kWh, your home electricity price, a public charging price and the share of charging done in public.
- Enter the EV's purchase price premium, any incentives you are sure to receive and other yearly cost differences, using a negative number if the EV costs less.
- Read the running costs, the saving per year, the total over your years and the payback of the higher price.
Formula
Gas per year = miles / mpg x gas price
Electricity per year = miles / (miles per kWh) x blended price
Blended price = home price x (1 - public share) + public price x public share
Total = (gas - electricity - other yearly difference) x years - (price premium - incentives)
The payback is the price premium minus incentives, divided by the yearly saving.
Twelve thousand miles a year
A gas car at 30 mpg and $3.50 a gallon uses 400 gallons for $1,400.00 a year. An EV at 3.5 miles per kWh uses 3,429 kWh. With 10% of charging in public at $0.45 and the rest at home at $0.16, the blended price is $0.189, so electricity costs $648.00.
With $300 less in other yearly costs, the saving is $1,052.00 a year. If the EV costs $8,000 more, over 8 years the EV comes out ahead by $416.00 and pays back the premium in about 7.6 years.
What drives the result
Three inputs matter most: how far you drive, the price gap between the two cars and the prices of gas and electricity. Heavy drivers save more per year, so they pay back the premium sooner. Cheap home charging helps, while a high share of public charging narrows the gap.
Your own prices are the key. The numbers in the fields are examples. Use the rate on your electric bill and the gas price you see, and test a few values to see how sensitive the answer is.
What is not included
Loan interest, depreciation, battery wear, home charger installation, taxes and changes in energy prices are not modeled, and each can move the answer. Incentives should only be counted when you are sure to receive them and their rules fit your situation.
For charging details use the EV charging cost calculator, for gas cost the fuel cost calculator, and for a wider view the total cost of car ownership calculator. The MPG calculator checks your gas car's real economy.
Assumptions and limits
- Every price and efficiency number is yours to set, and the examples are only samples.
- Prices stay the same over the years.
- Financing, depreciation, battery wear, charger installation, taxes and trip patterns are not modeled.
- The other yearly difference is EV minus gas car, so a negative number means the EV costs less.
Frequently asked questions
Is an EV cheaper than a gas car?
On running costs it often is, but the purchase price can be higher. This tool adds both sides for your miles and prices and shows the total over your years and the payback time.
How is the cost per mile worked out?
For gas it is the gas price divided by mpg. For an EV it is the blended electricity price divided by miles per kWh. The tool shows both.
Why include public charging separately?
Public charging usually costs more per kWh than charging at home, so the share you do in public changes the blended price. You set both prices and the share.
What if the EV is cheaper to buy?
Enter a negative number for the price difference. Then there is no payback period, and the whole running saving adds to your total.