How EV vs gas calculator Works
Energy cost is arithmetic; the rest is assumptions
Gas car energy cost = miles ÷ MPG × gas price. EV energy cost = miles ÷ miles-per-kWh × electricity price. The comparison is exact given your inputs — the inputs are where honesty lives. At $3.45 gas, 30 MPG, $0.15/kWh, and 3.0 mi/kWh: the gas car costs $115/month at 1,000 miles; the EV charges $50 — a $780/year gap.
Where the assumptions bite
- Charging access decides everything. Home charging at residential rates is the EV's superpower. Rely on DC fast chargers and the "fuel" advantage can shrink to nearly nothing — DCFC pricing commonly runs 2–3× residential rates.
- Cold weather cuts EV efficiency 10–30% (cabin heat, battery chemistry). Northern climates should discount the mi/kWh figure.
- Real MPG beats sticker MPG by less than EV figures vary. Use your measured number from the MPG calculator.
What this calculator deliberately ignores
Purchase price, depreciation, insurance, maintenance, and battery degradation all matter to total ownership cost — often more than fuel. Energy cost is the cleanest, most personal comparison (it depends only on your rates and miles), so it gets its own tool. As a rule of thumb: maintenance savings favor EVs by pennies per mile, while purchase-price gaps can erase years of fuel savings — compare specific trims, not philosophies.