EV Charging Cost Calculator

Work out the energy the charge adds, then price it: energy (kWh) = battery capacity x (target per cent minus starting per cent) / 100, and cost = energy x rate (p/kWh) / 100 in pounds. Charging a 60 kWh battery from 20 to 80 per cent adds 36 kWh; multiply that by the pence per kWh you actually pay at the socket. The calculator runs the same charge against your home and public rates side by side.

Divide the cost of the charge by the range it adds. Range added = energy (kWh) x efficiency (miles per kWh), so cost per mile = rate (p/kWh) / efficiency. A vehicle achieving 3.5 miles per kWh charged at a given pence per kWh costs that rate divided by 3.5 for each mile. This makes the efficiency figure as important as the tariff: a van at 2.5 miles per kWh costs 40 per cent more per mile than a car at 3.5 on the same rate.

Two reasons: battery care and charging speed. Lithium-ion packs age faster when held at very high states of charge, so manufacturers commonly recommend a day-to-day ceiling around 80 per cent, reserving full charges for long trips. Charging also slows sharply above roughly 80 per cent as the battery management system tapers the current, so on a public rapid charger the last 20 per cent takes disproportionately long for the energy it adds.

Usually, for structural reasons rather than any fixed price gap. Domestic electricity carries VAT at 5 per cent while public charging is standard-rated at 20 per cent, and public networks must recover hardware, grid connection and maintenance costs through the per-kWh price. Off-peak EV tariffs widen the gap further by pricing overnight charging below the daytime rate. Enter your actual home tariff and a real public rate to see the difference for your own vehicle.

Use the real-world miles per kWh from the vehicle's trip computer over a representative period, not the official WLTP figure, which is set in laboratory conditions. Cars typically achieve around 3 to 4 miles per kWh; vans and larger SUVs sit lower. Efficiency also drops in winter because cabin heating and battery conditioning draw from the pack, so it is worth running the calculator with a summer and a winter figure to bracket the cost.

Yes. The onboard charger converts AC from the socket to DC for the battery and loses some energy as heat in the process, so the meter records slightly more energy than the battery stores. Losses are higher on slow AC charging at low power and lower on DC rapid units, where conversion happens in the charger. The calculator prices the energy that reaches the battery, so treat the result as a slight underestimate of the metered cost.