How Much Does It Cost to Charge an EV? The Formula

Key Takeaways

• The formula is one multiplication: kWh added × your rate. A 75 kWh fill at the 18.44¢ national average ≈ $13.80; a real night's top-up ≈ $2–3.
• Per mile it lands around 5–6¢ at home — set against gasoline's per-mile cost, the gap is the EV's entire fuel argument.
• Rates are everything: off-peak EV plans cut the number, DC fast charging multiplies it, and state rate spreads (12¢–47¢) move it threefold.
• With rooftop solar, the marginal cost of a solar-window charge approaches the panels' near-zero production cost — the endgame this site keeps arriving at.

The formula and its honest inputs

Cost = kilowatt-hours added × price per kilowatt-hour. That's the entire science; the craft is using your numbers. Packs run roughly 60–100+ kWh, but you rarely fill from empty — a typical American day (~37 miles at ~3.5 mi/kWh) consumes 10–12 kWh, so the realistic nightly line is:

• Daily top-up: ~11 kWh × 18.44¢ (EIA national average, May 2026) ≈ $2.03
• Full 75 kWh fill: ≈ $13.83 at the same rate
• Monthly driving (≈1,125 mi): ≈ $60 at average rates — the "second EV bill" households actually see

State spread reshapes everything: the same fill costs ~$9 in a 12¢ state and ~$25 in a 33¢ one — which is why our state worth-it guides treat the electricity rate as the master variable for solar and EVs alike.

Arithmetic at stated assumptions (3.5 mi/kWh; your model's EPA figure on FuelEconomy.gov). Fast-charge pricing varies by network and state.

The three levers that move your number

Lever one: when you charge. Time-of-use and EV-specific tariffs price overnight electricity at the day's floor — scheduling the car into that valley (one setting, once) is the cheapest optimization in all of EV ownership. Our TOU guide runs the strategy.

Lever two: where you charge. Home is the grocery store; DC fast charging is the restaurant — two to four times the per-kWh price, justified by road-trip speed and ruinous as a lifestyle. Households without home charging access feel this hardest, which is the honest asterisk on all EV fuel-savings claims.

Lever three: who makes the electrons. A rooftop array's output, once the hardware is paid down, costs approximately nothing to produce. Charge in the solar window (or through full-retail net-metering credits where they survive) and the per-mile figure heads toward the decimal dust — roughly 8 panels' worth of production covers average driving, per our sizing math. That loop — roof to battery to wheels — is the cheapest recurring mile in American transportation, and the reason this site pairs the two technologies at all.

Against gasoline, briefly and fairly

At home-average rates, 5–6¢ a mile faces a gasoline figure that varies with pump prices and your old car's thirst — but for typical sedans and typical prices, the EV's per-mile fuel cost runs at a large fraction below it, off-peak widens the gap, and solar effectively closes the ledger. Fast-charging-only ownership, conversely, can approach gasoline parity — the exception that proves where the savings actually live: in your garage, on your tariff, ideally under your panels.

Keep reading: EV charging times · charging levels · charging in the rain.