How long does it take to charge an electric car?

Divide the wall energy required by the lower of the charging station power and the vehicle's accepted power, then account for reduced power above the fast-charge taper threshold. Temperature and battery conditioning can make a real session longer.

How much does it cost to charge an EV?

Multiply energy drawn from the grid—not only energy stored in the battery—by the electricity price. Grid energy includes the charging loss entered in the calculator.

What size home charger do I need?

A useful minimum replaces the energy used by typical daily driving during the hours the car is plugged in. It depends on daily miles, vehicle efficiency, charging losses and the available charging window.

EV Charging Calculator: Time, Cost and Home Charger Size

Calculate EV charging time, wall energy, session cost, range added, home charger size and annual savings versus gasoline.

See the energy behind an EV charge

Model the battery window, wall losses, charger and vehicle limits, optional fast-charge taper, trip range and annual fuel comparison—without assuming the plug's advertised power always reaches the battery.

Usable battery capacity (kWh)Starting charge (%) Target charge (%)Charging loss (%) Charging station power (kW)Vehicle maximum input (kW) Taper starts at state of charge (%)Average power after taper (%) Electricity price ($/kWh)EV efficiency (miles/kWh) Daily driving (miles)Available charging window (hours) Annual driving (miles)Gas vehicle efficiency (mpg) Gasoline price ($/gallon)

Formulas that keep the estimate honest

Battery energy = usable capacity × change in state of charge. Grid energy = battery energy ÷ (1 − charging loss). Power is capped at the lower of the station and vehicle limits. Energy above the taper threshold uses the entered average tapered power.

Minimum overnight power replaces daily driving energy inside the available window and includes charging loss. Annual EV cost uses annual miles, real driving efficiency, loss and your electricity rate.

Official guidance and limits

The EPA explains that battery capacity is measured in kWh, charging power in kW, and the vehicle caps the power it can accept. Its home charger calculator similarly sizes charging around miles that must be replenished rather than a full battery every night.

EPA home EV charger calculator · EPA charging details · DOE charging program guide

This is an energy and cost scenario, not an electrical load calculation, circuit design, installation quote or vehicle-specific charge-curve simulation.