EV Charging Time & Cost Calculator
How long a charge takes from battery size and charger power, and what it costs at your price per kWh
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Works out how long an electric car takes to charge, how much electricity it draws and what the charge costs, for a home charge or a fast-charger stop.
How to use
- Enter the "Battery capacity", "Current charge" and "Target charge".
- Pick a charger button or type the "Charger power"; the "Charging time" appears at once.
- Open "More settings" to change the charging loss or add the car's limit and the power above 80 %.
- Under "Price and efficiency", enter the "Price per kWh" (or "Two time bands") and the efficiency to see the cost and range added.
- Enter a "Trip distance" to estimate the charging stops.
How it works
- Energy into the battery = capacity × (target % − current %) ÷ 100. Grid energy = that ÷ (1 − loss %). Time = grid energy ÷ power.
- The 10 % loss and the 2.3 kW home-socket power are assumed values; replace them when you know yours.
- Fast charging often slows from around 80 %. Full power is assumed unless you enter an average power above 80 %.
- No tariff tables and no advice on charger installation or electrical supply.
Questions and answers
- How long does a 7 kW charger take?
- From 20 % to 80 % of a 64 kWh battery is 38.4 kWh; with 10 % loss that is 42.7 kWh from the grid, about 6 hours at 7 kW.
- How much does it cost to charge an electric car?
- Grid energy × price per kWh. 42.7 kWh at 300 per kWh is about 12,800 in your currency.
- Why does fast charging slow down after 80 %?
- The battery finishes at a constant voltage while the current falls, so the last part takes longer.
- Does the efficiency include charging losses?
- No. Enter the figure from the trip computer; the loss is added separately, so the cost per km includes it.