Home EV Charging Cost UK

How home EV charging cost is calculated

The basic calculation is grid energy in kWh multiplied by your electricity unit rate in pence per kWh. Because charging is not perfectly efficient, the grid usually supplies more energy than the battery gains. At 90% efficiency, adding 36.0 kWh to the battery uses about 40.0 kWh from the grid.

A domestic standing charge is normally a whole-home daily cost rather than a charge that only applies to your EV. The calculator lets you include a time-based portion if you want to allocate it to a charging session, but many comparisons leave it out.

Standard tariff vs off-peak EV tariff

Using the editable defaults, a 60 kWh EV charged from 20% to 80% costs about £9.87 on a 24.67p/kWh standard home rate, before any standing charge allocation. The same session costs about £3.48 at 8.7p/kWh.

Off-peak EV tariffs can be much cheaper overnight, but the daytime unit rate and standing charge can be different. Check the full tariff, your smart meter compatibility, and your usual household usage before switching.

3-pin plug vs 7kW wallbox

A 3-pin plug is slow, often around 2.3 kW, so it may be useful for occasional or emergency charging but can take many hours. A typical home wallbox is around 7 kW or 7.4 kW, which is more practical for overnight charging and usually integrates better with scheduled off-peak charging.

Charger power affects charging time, not the energy needed. If two chargers add the same kWh at the same tariff and efficiency, the electricity cost is broadly the same, but the faster charger finishes sooner.

Worked home charging examples

• 36 kWh added to the battery at 90% efficiency uses 40 kWh from the grid.
• 40 kWh at 24.67p/kWh costs about £9.87 before any standing charge allocation.
• 40 kWh at 8.7p/kWh costs about £3.48, which shows why overnight EV tariffs can be attractive.