Methodology, sources and limits

Data

• Electricity: EIA Electric Power Monthly, Table 5.6.B (average residential price, year-to-date through July 2026, cents/kWh) and 5.6.A (July 2026 month). These are preliminary EIA estimates. Source.
• Gasoline: EIA Gasoline and Diesel Fuel Update, U.S. regular retail price, week of 10/19/26 (released October 20, 2026). EIA publishes its own series for CA, CO, FL, MA, MN, NY, OH, TX, WA; other states use their EIA regional (PADD) average, so local prices can differ by tens of cents. AK and HI use the "West Coast less California" series, which likely understates their prices. Source.
• EIA content is U.S. government work and may be reproduced with attribution.

Assumptions (all editable in the calculator)

• EV efficiency 0.3 kWh/mile (typical mid-size EV; EPA label values for current EVs range roughly 0.25-0.40).
• Gas car 28 mpg. Miles per year 12,000.
• 80% home charging at the state residential average; 20% public DC fast charging at $0.45/kWh. This price is our rough assumption (public fast-charging prices vary widely by network and place), not an EIA figure.
• Formula: EV ¢/mile = kWh/mi × (home share × home rate + (1 − home share) × fast rate). Gas ¢/mile = price ÷ mpg. Annual savings = (gas − EV) × miles.
• Appliance costs = typical kWh used × state residential price. Wattages are typical figures, not measurements of your device.

What is not included

Vehicle price and financing, tax credits or rebates, insurance, maintenance, depreciation and resale, home-charger installation, time-of-use or demand charges, cold-weather range loss, and differences between your utility and the statewide average. A state average is not your bill.

Corrections

If you spot an error, tell us via the contact on the About page. We will check it against the EIA source and fix it.

General information only. Not financial, tax or purchasing advice.

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