Calculate energy added to the battery
Multiply usable battery capacity by the percentage-point increase in state of charge. A 60 kWh usable battery charged from 20% to 80% gains about 36 kWh of stored energy.
Allow for charging losses
The charger must usually supply more energy than the battery stores. If overall charging efficiency were 90%, storing 36 kWh would require about 40 kWh from the wall.
Apply the tariff that matches the charging time
Multiply wall energy by your electricity price. If you use a time-of-use tariff, apply the price for the hours in which the charging session actually occurs.
Do not confuse charger power with session energy
A 7.4 kW home charger describes the approximate charging power available, not the energy used by every session. Energy depends on both power and charging time.
Public charging can have extra fees
Some public networks may add session, time, parking or other charges. If pricing is not purely per kWh, include those separately from the energy calculation.
Home charging speed and typical overnight sessions
A standard home wallbox typically delivers between 3.6 kW and 11 kW, meaning an overnight charge of six to eight hours can comfortably replenish a substantial portion of most EV batteries from a partial charge. Because most home charging happens overnight while a car sits unused anyway, the practical inconvenience of home charging is usually low even though the session itself can take several hours — far longer than a public rapid charger, but at a much lower cost per kWh.
Off-peak tariffs and EV charging
Many European suppliers now offer EV-specific or general off-peak tariffs with significantly cheaper overnight rates, specifically to encourage exactly this kind of flexible, schedulable load. If your charger or vehicle supports scheduled charging, shifting sessions into an off-peak window can meaningfully reduce cost without changing how much energy you use at all — see our guide to European electricity billing for more on tariff types.
Frequently asked questions
How much does a full home charge typically cost?
This depends on your battery size and home tariff; use our EV charging cost calculator with your battery's kWh capacity and your own price per kWh for a specific figure.
Is a faster home wallbox always better value?
A faster wallbox reduces charging time but does not change the total kWh used or its cost; it is mainly useful if you need a full charge in a shorter overnight window.
Does charging efficiency loss matter for home charging?
Yes, some energy is lost as heat during AC-to-DC conversion inside the vehicle, so energy drawn from the wall is typically a little higher than the energy that actually reaches the battery.
Should I charge to 100% every night at home?
Many manufacturers recommend a lower routine daily charge limit, such as 80%, for long-term battery health, reserving 100% charges for before longer trips; this is a battery-health consideration rather than a cost one.
Can I use this guide's figures for a plug-in hybrid?
The same watts-to-kWh-to-cost principles apply, though plug-in hybrid batteries are typically much smaller, so charging sessions and costs will be proportionally lower.
