Gas vs Electric Cost Calculator

Gas vs. electric vehicle (EV) cost comparison goes well past the sticker price.
It has to weigh fuel against electricity, the maintenance gap, the insurance difference, and whatever incentives apply, across the whole time you keep the car.

The core formulas:

Annual Gas Fuel Cost = (Annual Miles / MPG) × Gas Price per Gallon

Annual EV Electricity Cost = (Annual Miles / MPGe) × Electricity Price per kWh × 33.7

The form above asks for miles per kWh, where bigger is better, so the version the calculator actually runs is:

Annual EV Cost = (Annual Miles ÷ Miles per kWh) × Price per kWh

Payback (years) = Extra Purchase Price ÷ (Annual Fuel Saving + Annual Maintenance Saving)

What each variable means:

• MPGe: miles per gallon equivalent; the EPA uses 33.7 kWh = 1 gallon for comparison purposes
• Miles per kWh: most EVs manage 3 to 4 in real-world driving. Some specifications quote the reciprocal, kWh per mile, which runs 0.25–0.35. Divide either into 1 to get the other: 0.30 kWh/mile is 3.3 miles/kWh, and putting 0.30 into the box above instead would overstate the running cost elevenfold.
• Incentives: US federal EV tax credit up to $7,500 plus state incentives
• Maintenance savings: EVs have no oil changes, fewer brake jobs (regenerative braking), and no transmission service

Worked example: Gas car: $30,000, 30 MPG, $3.50/gallon, $1,200/year maintenance. EV: $40,000 − $7,500 incentive = $32,500 effective, 3.3 miles per kWh, $0.14/kWh, $600/year maintenance.

Annual miles: 13,000.

Annual gas cost = (13,000 ÷ 30) × $3.50 = $1,517 Annual EV electricity cost = (13,000 ÷ 3.3) × $0.14 = $552 Annual fuel saving = $1,517 − $552 = $965 Annual maintenance saving = $1,200 − $600 = $600 Annual EV advantage = $1,565/year Effective price difference = $32,500 − $30,000 = $2,500 Payback period = $2,500 ÷ $1,565 = 1.6 years

The payback line is the one worth arguing about, because it swings entirely on the incentive. Take the $7,500 away and the price gap is $10,000, which at $1,565 a year takes 6.4 years to earn back. That is about as long as the average person keeps a car, so with no incentive the two choices are roughly a wash and the decision comes down to something other than money.

Home charging against public fast charging: home runs about $0.04 a mile, while DC fast charging can hit $0.20–$0.30 a mile, which is nearly as expensive as petrol.