How this calculator works
The energy a car uses on a trip is its consumption per 100 km multiplied by the distance divided by 100. Paying for that energy at a price per kilowatt hour gives the trip cost. Charging is not perfectly efficient: some grid energy is lost in the charger, the onboard converter and the battery, so the grid energy is the battery energy divided by the charger efficiency. The charging session reports only the energy between the two state-of-charge limits you entered. Range is the usable battery capacity divided by consumption, which is an estimate because speed, temperature, hills and heating change consumption.
Formula
Trip energy (kWh) = distance (km) x efficiency (kWh/100 km) / 100. Trip cost = trip energy x price. Grid energy = battery energy / charger efficiency. Range = capacity / efficiency x 100. Cost per 100 km = efficiency x price.
Worked example
A car with a 75 kWh usable battery and 15.6 kWh/100 km consumption uses 15.6 kWh on a 100 km trip. At $0.16 per kWh the trip costs $2.50. A full charge from empty draws 75 / 0.9 = 83.33 kWh from the grid and costs $13.33. Charging from 20 to 80 percent adds 50 kWh to the battery, draws 55.56 kWh and costs $8.89.
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Frequently asked questions
Should I use usable or gross battery capacity?
Use usable capacity, because that is the energy the car can actually deliver. Gross pack size includes a buffer that is not normally accessible.
Why does the full charge cost more than capacity times price?
Charging losses mean the grid supplies more energy than the battery stores. The efficiency field accounts for those losses, so a lower efficiency raises the grid energy and the cost.
Is home charging cheaper than a fast charger?
Usually. Home electricity is often billed at a lower rate than a DC fast charging network, and home charging is typically more efficient. Enter the actual price and efficiency for the charger you use.
Why is my real range lower in winter?
Cold reduces battery performance and cabin heating draws significant energy. The range shown here uses one constant efficiency, so it is a mild-weather estimate rather than a worst-case winter figure.