Use vehicle efficiency, not charger power
A 7.2 kW charger does not necessarily draw maximum power for a fixed number of hours every day. Miles driven and vehicle efficiency determine how much battery energy must be replaced.
Account for charging losses
Some energy is lost in the charging equipment, battery conditioning, and conversion process. The calculator adds a loss percentage so the estimate reflects energy drawn from the wall rather than only energy stored in the battery.
Time-of-use plans can change the answer
If your utility has different peak and off-peak prices, enter the price that applies when the car normally charges. Demand charges, charger subscriptions, and public charging are outside this estimate.