Generally speaking, you can roughly estimate about 5 to 10 kilometers per kWh. This means that an electric car with a battery capacity of 40 kWh, under ideal conditions, would have a range of approximately 200 to 400 kilometers.

It is important to remember that this is only an estimate and the actual range may vary. Factors such as the use of air conditioning or heating, driving at high speeds, hilly terrain, and carrying additional loads like passengers or luggage, can all influence the actual range of the electric car.

To get a more accurate picture of the range of a specific electric car, it is best to refer to the specifications and information provided by the manufacturer, as well as the data and experiences of other owners of similar models.