How EV cost per mile is calculated
Electric cost per mile = electricity rate ÷ (miles-per-kWh × 0.9). The 0.9 factor accounts for the roughly 10% of energy lost as heat during AC home charging — an honesty adjustment many calculators skip. Gas cost per mile is simply price per gallon ÷ MPG.
Home vs public charging
These savings assume home charging. Public DC fast charging often costs 2–3× the residential electricity rate, which can erase the advantage — use it for road trips, and charge at home (ideally on an off-peak plan) for daily driving.
Frequently asked questions
How much does it cost to charge an EV at home?
At a typical US residential rate, an efficient EV costs roughly 5–7 cents per mile — usually less than half the per-mile cost of gasoline.
Why include a 10% charging loss?
Some energy is lost converting AC grid power into the battery. Ignoring it understates your true cost per mile.
Can gas ever be cheaper than an EV?
Yes — with expensive electricity (or heavy DC fast-charging use) and an efficient gas car, the comparison can flip. The calculator will show a negative saving when that happens.