US EV charging calculator — cost, range and charge time

The energy needed is your battery size in kWh multiplied by the percentage-point gap between your current and target charge (e.g. a 60 kWh battery going from 20% to 80% needs 60 × 0.6 = 36 kWh). Cost is that kWh figure multiplied by your rate in cents per kWh. Charge time is the same kWh figure divided by the charger's effective speed — whichever is lower of the charger's own rating and your car's maximum charge rate, since a car can't charge faster than its onboard charger allows even on a more powerful unit. DC fast chargers also slow down above roughly 80% to protect the battery, so the estimate above that point runs a little optimistic — the calculator flags this with a warning when it applies.

Electricity cost varies a lot by where you charge. Home charging on a time-of-use overnight rate is cheapest, typically around 10¢/kWh. Home charging on a standard flat residential rate runs closer to 16¢/kWh — the current US average. Public charging costs more because the network operator has to cover hardware, installation and running costs — Level 2 public chargers (ChargePoint, Blink and similar) average around 28¢/kWh, DC fast chargers (EVgo, Electrify America) around 44¢/kWh, and Tesla Supercharger around 35¢/kWh. Picking a charging location above sets the rate slider to that type's typical figure, which you can then drag to match your own actual tariff.

The miles you get per kWh isn't fixed — it depends on how and where you drive. City driving is the most efficient because frequent braking recovers energy back into the battery through regenerative braking. Highway driving at sustained 70+ mph is the least efficient, since aerodynamic drag rises sharply with speed and there's little opportunity to regenerate. This calculator applies a multiplier to your car's baseline efficiency depending on which driving style you select. Efficiency figures themselves come from EPA combined cycle ratings, which run roughly 15–20% lower than European WLTP figures for the same vehicles — worth knowing if you're comparing a car's advertised range against a UK or EU source. Cold weather, cabin heating and towing all reduce real-world range further, on top of the driving-style adjustment — typically by 20–30% in winter conditions, which the range panel flags separately.