The Per-Mile Math
EV cost per mile = weighted electricity price ÷ miles per kWh. Gas cost per mile = price per gallon ÷ MPG. Everything else — annual, five-year — is just those two numbers multiplied by how far you drive, which is why per-mile is the only fair way to compare a car you charge by the kilowatt-hour against one you fill by the gallon.
With the defaults above, the EV runs about 6.8¢ per mile and the 30-MPG gas car about 14.9¢ — the EV is roughly half the fuel cost per mile before you touch a single input. Push the public-charging share to 100% and the gap narrows sharply; drop it to 0 and it widens.
Home vs. Public Charging: The 2–4× Gap
Where you charge matters more than which EV you drive. Home electricity at the US average of about 18¢/kWh is the cheapest energy a car has ever run on — but public DC fast chargers commonly charge 35–56¢/kWh, two to four times as much. An EV driver who fast-charges everything can end up paying per-mile costs close to a hybrid's.
The practical takeaway from owner data: the more of your charging you can shift to home (or the workplace), the better the economics get. Even a 240V home charger's installation cost — typically $500–$2,000 — usually pays for itself within the first couple of years if it moves most of your charging off public rates.
Where the Default Numbers Come From
Electricity defaults to the US residential average of 18.3¢/kWh (October 2026, EIA/industry trackers — up ~5% year over year). Gasoline defaults to $4.48/gallon, the recent EIA regular-grade retail average; prices swing by state and season, so replace it with your pump price. EV efficiency of 3.5 mi/kWh sits mid-range — most current EVs fall between 2.5 (trucks, winter, highway) and 4.5 (efficient sedans, mild weather) per kWh.
What Fuel Savings Don't Cover
- Registration fees. Many states charge EVs an extra $100–$250/year to replace gas-tax revenue.
- Insurance and depreciation. Both can run higher for EVs; depreciation especially varies wildly by model.
- Home charger. Level 2 hardware plus installation, offset over time by cheap home miles.
- Maintenance. The good news — EVs skip oil changes and much of the drivetrain maintenance, which this calculator counts as pure upside on top of fuel savings.
Common Questions
How much does it cost to charge an EV at home?
Multiply the kilowatt-hours you need by your utility rate. At the US average of about 18 cents per kWh, a car that does 3.5 miles per kWh costs roughly 5 cents per mile — about $52 to drive 1,000 miles. Your actual electric bill's rate (printed on it) is the number to enter; time-of-use plans can cut it 30–50% if you charge overnight.
Is public charging as cheap as home charging?
No — public DC fast charging typically runs 35–56 cents per kWh, two to four times the average home rate. An EV fast-charged exclusively at 45 cents can approach a hybrid's fuel cost per mile. That's why the calculator has a separate public-charging share and rate: owners who charge mostly at home see the biggest savings; road-trip-heavy drivers see much less.
What EV efficiency should I enter for my car?
Most current EVs average between 2.5 and 4.5 miles per kWh. Efficient sedans in mild weather sit near 4; crossovers around 3–3.5; trucks and winter highway driving can drop below 2.5. Your car's trip computer or the EPA sticker's MPGe figure (divide MPGe by 33.7) gives your real number — the trip computer's lifetime average is the most honest source.
Why does the calculator compare per mile instead of per fill-up?
Because there are no fill-ups to compare. An EV 'fills' in kilowatt-hours and a gas car in gallons, so the only common unit is distance. Cost per mile = electricity price ÷ miles per kWh for the EV, and gas price ÷ MPG for the gas car. From there, annual and five-year comparisons are just multiplication by your mileage.
Related Calculators
- Fuel Cost Calculator — Trip and annual fuel costs for gas cars
- Gas Mileage Calculator — Compute your real MPG
- Electricity Cost Calculator — What any appliance costs to run, including your charger