Commentary / evidence-led analysis: Electric-car savings are often discussed as if one electricity price could settle the entire comparison with gasoline. It cannot. A fair U.S. comparison starts with the energy needed to drive the same distance and what a particular driver actually pays for that energy. Using the vehicle’s EPA kWh per 100 miles, the electricity tariff, the gasoline vehicle’s miles per gallon (MPG), and the price of gasoline produces an auditable cost-per-mile result.
Illustrative answer: A 30 kWh/100-mile EV charging at $0.18/kWh costs $5.40 per 100 miles. A 30-MPG gasoline car fueled at $3.60/gallon costs $12.00 per 100 miles. But if the same EV pays $0.45/kWh at public charging, its energy cost rises to $13.50 per 100 miles before other fees. The examples are mathematical scenarios, not current nationwide prices, actual measured vehicles or a guarantee of savings.
What does cost per mile really measure?
Fuel or electricity cost per mile divides the money spent on propulsion energy by the distance traveled. This common unit is useful because a kilowatt-hour and a gallon are not equivalent purchases and cannot be compared by price alone. A car consuming more energy may still have a lower total bill if its energy source is sufficiently less expensive; another car can reverse that result at a different charger or filling station.
The U.S. Department of Energy’s Alternative Fuels Data Center guidance uses electricity price and EV efficiency to explain charging expense. EPA’s electric-vehicle window-label guide provides the kWh/100-mile consumption measure needed for a like-for-like comparison.
Two formulas that make EV vs gasoline comparisons transparent
EV energy cost per 100 miles = (kWh per 100 miles) × (price per kWh).
Gasoline energy cost per 100 miles = (100 ÷ MPG) × (price per gallon).
Divide either answer by 100 to obtain cost per mile. Use the exact vehicle’s combined EPA estimates as a starting point, then replace them with representative real-world energy use if you maintain accurate records. Avoid quoting a manufacturer’s best-case highway range as if it were the same as a combined consumption rating.
Worked example: home charging versus gasoline
- EV consumption: assume 30 kWh/100 miles from the EPA label.
- Home electricity: assume an applicable energy tariff of $0.18/kWh.
- EV spending: 30 × $0.18 = $5.40 for 100 miles, or $0.054 per mile.
- Gasoline efficiency: assume 30 MPG and $3.60 per gallon.
- Gas spending: (100 ÷ 30) × $3.60 = $12.00 for 100 miles, or $0.12 per mile.
- Difference: $12.00 − $5.40 = $6.60 per 100 miles in this specific scenario.
At an illustrative 12,000 miles per year with the same cost assumptions throughout, the calculated energy-cost gap would be $792 a year. This is not a vehicle ownership saving because it excludes the vehicles’ purchase prices and other costs. It also does not promise the charging tariff or MPG will remain unchanged.
How public charging can reverse the comparison
The same 30 kWh/100-mile EV at a hypothetical public charging price of $0.45/kWh uses the following arithmetic: 30 × $0.45 = $13.50 per 100 miles. Under the same gas example at $12.00 per 100 miles, gasoline costs $1.50 less per 100 miles before any charging session, occupancy, parking or membership fees. Prices vary widely by station and contract; do not interpret these examples as current national averages.
| Example scenario | Assumed energy price | Energy cost / 100 mi |
|---|---|---|
| EV, home charging (30 kWh/100 mi) | $0.18/kWh | $5.40 |
| EV, higher-cost public charging (30 kWh/100 mi) | $0.45/kWh | $13.50 |
| Gasoline car (30 MPG) | $3.60/gallon | $12.00 |
Electricity prices can differ for off-peak home charging and higher-power public charging. Actual utility charges may include fixed fees, demand or time-of-use components, taxes or other costs. Public charging operators may have session and idle fees. The relevant price is the cost you truly pay for the energy delivered under your billing arrangement.
How to calculate the break-even electricity price
For a driver deciding whether the EV is less expensive to fuel than a specified gasoline car, solve for the electricity price at which the two energy costs per 100 miles are equal:
Break-even electricity price ($/kWh) = ((100 ÷ gasoline MPG) × gasoline price per gallon) ÷ EV kWh/100 miles.
With the running example: (($3.60 × 100 ÷ 30 MPG) ÷ 30 kWh) = $0.40/kWh. Below that illustrative energy price, the EV has lower per-mile energy spending on these assumptions; above it, the gasoline vehicle does. This comparison ignores non-energy charging fees and does not claim that an EV’s ownership cost is lower at the break-even point.
The threshold changes if either vehicle’s efficiency changes. An EV using 40 kWh/100 miles will have a different break-even tariff than one using 25 kWh/100 miles. Equally, a 45-MPG hybrid has a different gasoline energy cost from a 25-MPG SUV.
The common mistake: double-counting charging losses
EPA’s published kWh per 100 miles already includes standardized charging losses. The joint EPA/DOE FuelEconomy.gov data downloads page expressly states that EV window-label kWh/100-mile estimates include charging losses. The EPA vehicle testing explanation also says the estimates reflect Level 2 AC charging losses.
Consequently, taking a window sticker’s 30 kWh/100 miles and adding an arbitrary extra 10% charging-loss penalty before calculating household electricity cost would double-count a factor already reflected in the rating. By contrast, if you start from a vehicle display that describes energy consumed from the battery rather than a wall-based electricity measurement, wall charging losses need separate consideration. Mixing those two bases makes comparisons misleading.
Direct-current public charging can involve different equipment, efficiency and billing arrangements than the EPA’s standardized AC test. For a personally accurate budget, compare the actual billed kWh and miles traveled over several ordinary trips rather than relying on a single idealized cycle.
Why battery size is not the same as energy cost
A 75-kWh battery pack’s nominal capacity does not mean a particular driver uses 75 kWh for every trip, just as a 15-gallon fuel tank does not mean every drive burns 15 gallons. Efficiency relates energy use to distance. A car consuming 30 kWh/100 miles requires a different amount of purchased electricity over 1,000 miles than one consuming 40 kWh/100 miles, regardless of battery-pack nameplate size.
For explanations of charge losses and billing, see our guide to charging losses and energy measured at the wall. The cost of public idle or congestion fees is discussed separately in our public charging idle-fee guide.
Fuel cost is not total cost of ownership
An EV can have lower energy cost per mile and still cost more to own over a particular period. The ownership calculation also includes purchase price, financing, registration, insurance, depreciation, tires, repairs, charging equipment and resale value. An inexpensive used EV, a high-mileage hybrid and a premium electric truck should not be forced into a single universal savings claim.
The Department of Energy’s Vehicle Cost Calculator methodology accounts for mileage and vehicle use when comparing fuel requirements. Drivers who cannot install home charging, who travel frequently or who face unusually high electric tariffs may see different outcomes than those who can charge at home during off-peak periods.
Four questions readers should ask of any EV savings headline
- Which exact vehicle and trim is being compared, and what are their EPA efficiency estimates?
- Does the calculation use home electricity, public charging or a realistic combination?
- Are the amounts current prices, measured personal bills or merely hypothetical examples?
- Does the claim cover energy expense only, or is it using purchase and depreciation data to support an actual ownership-cost conclusion?
A good comparison allows the reader to substitute local prices and reproduce the arithmetic. This editorial’s position is methodological: transparent cost-per-mile calculations are more informative than a categorical claim that one powertrain is always cheaper.
How to make a comparison with your own numbers
Record the actual kWh billed for several EV charging sessions and the miles driven between them, along with the charges per session. For gasoline, record gallons purchased and miles traveled across comparable use. Remove trips with incomplete fill-ups or unrecorded charging only if you clearly explain that adjustment; seasonal and highway-heavy trips should be represented rather than cherry-picked away.
For an official starting point, compare the relevant vehicles’ entries in FuelEconomy.gov and use the DOE’s home charging cost explanation. Our electric-car charging price formula guide goes further into charging-session cost, while our EPA window-sticker guide explains the ratings.
Sources and image disclosure
Primary references: DOE Alternative Fuels Data Center: Home Charging, EPA/DOE vehicle data and charging-loss note, EPA test methods, and DOE cost-calculator methodology.
Original editorial analysis prepared November 9, 2026. All illustrative price, consumption and yearly mileage inputs are explicitly hypothetical and not quotes for specific states or vehicles. Featured image: a real public EV charging point in Saint Augustine, Florida, photographed by GA Kevin in July 2025, CC0 1.0 / Wikimedia Commons. The photo does not show the assumed tariffs or measured charging savings.
Sık Sorulan Sorular
How do you calculate EV cost per mile?
Use (EPA kWh per 100 miles ÷ 100) × electricity price per kWh. For 30 kWh/100 mi at $0.18/kWh, the result is 5.4 cents per mile.
How do you calculate gas cost per mile?
Divide the local gasoline price per gallon by the vehicle's MPG. For $3.60 per gallon and 30 MPG, the result is 12 cents per mile.
When is public fast charging more expensive than gasoline?
It depends on the price and efficiencies being compared. In the article's illustrative 30 kWh/100 mi EV vs 30 MPG gas car at $3.60/gallon, the energy-cost break-even price is $0.40/kWh, before additional charging fees.
Do EPA EV kWh/100-mile figures include charging losses?
Yes. EPA and DOE state that fuel-economy label consumption estimates account for charging losses under standardized test conditions. Do not automatically add another loss factor to the label figure.
Does lower fuel cost mean an EV is cheaper to own?
No. A fuel-cost comparison excludes purchase and resale price, financing, registration, insurance, tires and repairs, among other ownership costs.
