EV Charge Every number on EV Charge Math comes from a public source and a formula you can check yourself. This page explains both, so you can decide how much to trust us.
The formula
Cost to drive = miles × (kWh per 100 miles ÷ 100) × price per kWh
Example: 1,000 miles in a Tesla Model Y Long Range (27.5 kWh/100 mi) at the U.S. average of 18.31¢ per kWh = 1,000 × 0.275 × $0.1831 ≈ $50.
Where the data comes from
- Electricity prices: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, average residential price by state. We currently use July 2026 and compare it with July 2025.
- Gas prices: EIA weekly retail gasoline prices, regular grade, week of October 12, 2026. The EIA publishes figures for nine states; for the rest we use the EIA regional (PADD) average and say so on the page.
- Vehicle efficiency: fueleconomy.gov (U.S. Department of Energy and EPA), combined kWh per 100 miles. EPA measures this from the wall outlet, so charging losses are already included.
- Miles driven: we use 12,000 miles a year as a round default. Federal highway data puts the average light-duty vehicle at about 11,000 miles and the average licensed driver at about 13,700.
Assumptions and limits
- The gas comparison uses a 30-mpg car. Change it in the calculator if you drive something else.
- State averages include all residential customers, not just EV owners on special rates.
- We don’t include charger installation, fixed monthly fees, battery degradation, or public fast charging in the per-mile figures. Those get their own guides.
- Real-world efficiency is worse in cold weather and at highway speeds.
Updates and corrections
We refresh electricity prices when the EIA publishes new monthly data and gas prices regularly. Each page shows its last update date. If you find an error, write to us and we will fix it and record it here.
Correction log
- October 18, 2026: site launched with July 2026 EIA data. No corrections yet.