EV vs gas cost calculator
Enter the miles you drive, the gas car's mpg and local gas price, and the EV's efficiency and your electricity rate, to see the cost per mile for each and the saving.
The EV is cheaper by
$58.89
$56.10 in electricity against $114.99 in gas
How to use it
- Enter the miles you want to compare over. A typical month is 1,000; a year is 12,000 to 15,000.
- Enter the gas car's real-world mpg and your local price per gallon.
- Enter the EV's efficiency in kWh per 100 miles, from the sticker or the trip computer, and the price per kWh from your electricity bill.
- Adjust the charging loss if you know it, then read the cost per mile for each and the saving.
Worked example
1,000 miles a month. Gas car at 30 mpg with gas at $3.45; EV at 30 kWh/100 mi, home electricity at $0.17 per kWh, 10% charging loss.
Gas: 1,000 ÷ 30 = 33.33 gallons × $3.45 = $114.99, or 11.5 cents a mile. Electricity: 1,000 × 30 ÷ 100 = 300 kWh, plus 10% loss = 330 kWh × $0.17 = $56.10, or 5.6 cents a mile.
The EV saves $58.89 a month, and a gas car would need 61.5 mpg to match it. On public fast charging at $0.50 a kWh the EV would cost $165.00, more than gas.
How this is calculated
The gas side is simple: miles divided by miles per gallon gives gallons, and gallons times the price gives the cost. The electric side works the same way with the EV's efficiency, which car makers quote in kilowatt-hours per 100 miles: miles times that figure divided by 100 gives the energy the car uses. Charging isn't perfectly efficient, so the energy you pay for is a little more than the energy that reaches the battery; the calculator adds the loss percentage before pricing it at your rate. The miles-per-gallon-equivalent line answers a question people ask a lot: what mpg would a gas car need to match the EV's running cost at today's prices. It's a running-cost comparison only, without purchase price, insurance, maintenance or depreciation.
gas cost = miles ÷ mpg × price per gallon
energy used = miles × kWh per 100 miles ÷ 100
energy bought = energy used × (1 + charging loss %)
EV cost = energy bought × price per kWh
mpg equivalent = miles ÷ (EV cost ÷ price per gallon)
Rates, sources and limits
Last reviewed 23 Sep 2026 by the CalcRabbit team. Estimates only, not financial, tax or medical advice.
Frequently asked questions
What efficiency should I enter for the EV?
The window sticker gives kWh per 100 miles for the official cycle; real-world figures run 10% to 20% higher in winter and at highway speeds. Most compact and mid-size EVs sit between 25 and 32 in mild weather; large SUVs and trucks 40 to 50. Your car's trip display shows the actual number.
Why add charging losses?
Converting AC from the wall to DC in the battery, plus keeping the battery at temperature, wastes some energy, so the meter reads more kWh than the car reports. Around 10% is typical for a home Level 2 charger, more for a 120 V trickle charge, and it matters because you pay for what the meter reads.
Does time-of-use pricing change this much?
A lot. Many utilities offer EV or off-peak rates of 8 to 12 cents a kWh overnight, against 15 to 30 cents during the day. Charging on the cheap rate can halve the electricity line. Enter the rate you'll actually charge at.
What's not included?
Purchase price, financing, insurance, tyres, maintenance, registration and any EV road fee your state charges. Those can go either way; an EV's cheaper servicing and a higher purchase price are the usual big items. This calculator is the fuel-versus-electricity piece only.