Methodology
Every number on OutletBill is calculated from official U.S. government data. Data last updated October 2026; electricity data runs throughAugust 2026 and gasoline through September 2026.
Sources
- Vehicle efficiency and range: EPA / DOE fueleconomy.gov vehicle records: combined electricity consumption (kWh per 100 miles), EPA range, and combined MPG for the gas comparison vehicles.
- Electricity prices: U.S. Energy Information Administration, average residential retail price by state, monthly (Electric Power Monthly, Form EIA-861M).
- Gasoline prices: U.S. Energy Information Administration, monthly retail gasoline prices by state or region.
- Driving distance: Federal Highway Administration, Highway Statistics 2024 (published February 2026):Table VM-1 (vehicle-miles traveled by light-duty vehicles, short and long wheelbase) andTable DL-22 (licensed drivers).
Formulas
- Cost per 100 miles = EPA kWh per 100 miles × electricity rate.
- Cost per full charge = EPA range × kWh per 100 miles ÷ 100 × rate: the cost of the electricity needed to drive the full EPA range. EPA does not publish usable battery capacity, so this is not a battery-size figure.
- Monthly and annual cost = miles driven × kWh per 100 miles ÷ 100 × rate.
- Gas car cost = miles driven ÷ EPA combined MPG × gasoline price.
- No extra charging-loss factor. EPA measures EV consumption at the wall outlet, so its kWh figures already include charging losses.
- Time-of-use rates (calculator only): effective rate = standard rate × (1 − off-peak share) + off-peak rate × off-peak share.
Assumptions
- Electricity rate:the average of the latest 12 months, weighted by kWh sold (total revenue ÷ total kWh), which smooths out seasonal swings.The U.S. average is currently 18.0¢/kWh.
- Gasoline price: the average of the latest 12 monthly prices, using premium where EPA lists premium fuel for the comparison vehicle.
- Driving distance: 1,016 miles a month, the FHWA average of 12,193 miles per licensed driver per year (2,924,108 million light-duty vehicle-miles ÷ 239,824,944 licensed drivers in 2024), divided by 12. Light-duty vehicles are cars, SUVs, pickups and vans; trucks, buses and motorcycles are excluded. Change it in the calculator.
- Charging location: all charging at home at the residential rate. Public fast charging usually costs more and is not included.
- Model year: the newest model year for which EPA has published the trim we use for headline figures and at least50% of the previous year's trims. EPA adds next-year vehicles gradually.
Vehicles and gas comparisons
Comparison vehicles match the EV's size class and segment; when two choices are close, we use the one with the higher MPG, which makes the EV's savings estimate more conservative.
| EV (headline trim) | Gas comparison | Why |
|---|---|---|
| 2026 Tesla Model Y Long Range AWDBest-selling trim (Long Range AWD). | 2027 Honda CR-V FWD, 30 mpg (regular) | Honda CR-V FWD (1.5T, non-hybrid): best-selling compact SUV segment. |
| 2026 Tesla Model 3 Standard RWDEntry trim (Standard RWD). | 2026 Honda Accord, 32 mpg (regular) | Honda Accord (1.5T, non-hybrid): mainstream midsize sedan. |
| 2027 Chevrolet Equinox EV FWDEntry drivetrain (FWD). | 2027 Chevrolet Equinox FWD, 27 mpg (regular) | Chevrolet Equinox FWD (gas): same nameplate and body. |
| 2026 Ford Mustang Mach-E RWDEntry trim (RWD, standard-range battery). | 2026 Ford Escape FWD, 30 mpg (regular) | Ford Escape FWD (1.5L): Ford compact SUV. |
| 2027 Hyundai Ioniq 5 Standard RangeEntry trim (Standard Range RWD). | 2026 Hyundai Tucson FWD, 28 mpg (regular) | Hyundai Tucson FWD (2.5L, non-hybrid): Hyundai compact SUV. |
| 2026 Honda Prologue FWDEntry drivetrain (FWD). | 2026 Honda Passport AWD, 21 mpg (regular) | Honda Passport AWD (3.5L V6): Honda midsize SUV, same size class. |
| 2026 Kia EV9 Standard Range RWDEntry trim (Standard Range RWD). | 2027 Kia Telluride FWD, 22 mpg (regular) | Kia Telluride FWD (non-hybrid): Kia three-row SUV. |
| 2026 Rivian R1S Dual Standard (20-in)Entry trim (Dual Standard, 20-inch wheels). | 2027 BMW X5 40 xDrive, 26 mpg (premium) | BMW X5 xDrive40 (premium fuel): luxury midsize SUV. |
| 2027 Cadillac Lyriq RWD (11 kW charger)Entry trim (RWD, standard 11 kW onboard charger). | 2026 Cadillac XT5 FWD, 24 mpg (premium) | Cadillac XT5 FWD (2.0T, premium fuel): Cadillac midsize SUV. |
| 2026 Nissan Leaf 75 kWh (18-in steel wheels)Entry trim (S+, 18-inch steel wheels). | 2027 Nissan Kicks FWD, 31 mpg (regular) | Nissan Kicks FWD: Nissan small crossover. |
Gasoline price series by state
EIA publishes retail gasoline prices for only some states. Elsewhere we use the state's Petroleum Administration for Defense District (PADD) region.
- California: EIA California series
- Florida: EIA Florida series
- New York: EIA New York series
- Texas: EIA Texas series
- Washington: EIA Washington series
Updates and quality checks
Data is refreshed monthly. Before anything is published, an automated check stops the update if any state's data is missing, if a price moves more than30% from one month to the next without review, if a vehicle disappears from EPA's data, or if a value falls outside a plausible range (for example, electricity between 5¢ and 60¢ per kWh).