From plug to battery
Calculate energy drawn from the grid and the cost of charging an electric car between two charge levels.
Method
Stored energy = battery capacity × charge-level change. Grid energy = stored energy ÷ charging efficiency.
Charging an 80 kWh battery from 20% to 80% stores 48 kWh; at 90% efficiency the grid supplies 53.3 kWh.
Use responsibly
The usable battery capacity may differ from the advertised capacity. Charging losses vary by car, temperature and charger.
Last reviewed: 20 July 2026
Calculation and copy checked for this release.
