EV charging calculator
VehiclesHow long and how much does it cost to charge your electric car?
Charging time, energy from the grid and cost for any charger, with losses and the car's own limits.
What you enter stays on your device while you use this tool. Opening a shared link sends the settings in its address to HowToolbox to prepare the page.
Car, price and losses
Cost of the charge
$11.67
4 hr, 15 min to charge 10 → 80 %, 46.7 kWh from the grid
The charge in detail
- Energy into the battery
- 42 kWh
- Energy from the grid
- 46.7 kWh
- Charging losses (typical)
- 10 %
- Charging power (limited by the charger)
- 11 kW
- Charging time
- 4 hr, 15 min
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A simple model, not your car's real curve: AC power stays constant, DC power holds to 80 % and then tapers. Real charging varies with the car, the temperature and the state of charge.
Charging time, energy from the grid and cost for any charger, with losses and the car's own limits.
How to use
- Enter the battery's usable capacity and the charge you start from and charge to.
- Choose AC for a wallbox or DC for a fast charger, then enter the charger's power and the car's own limit for that type.
- Enter your electricity price per kWh. Read the cost and the time, and open the detail for the energy and losses.
How it works
A battery stores less energy than the grid supplies: some of it turns into heat in the charger, the cable and the battery. So the energy from the grid is the energy into the battery divided by (1 − losses), and the cost is that grid energy times your price per kWh. Typical losses are about 10 % on AC and 8 % on DC, from published measurements (Idaho National Laboratory, the California ETCC, ADAC) that range from about 5 % to 20 %.
The car and the charger share the work, so charging runs at the lower of the charger's power and the car's limit (its onboard charger on AC, its DC peak on DC). On AC the power is held constant. On DC it is held up to 80 %, the point makers quote as "10–80 %", and then falls steadily to a fifth of the power at 100 %. Time is the energy divided by the power, added up over the charge.
Real curves differ by car, battery temperature and state of charge, and chargers may share power between cars. Treat the time as a fair guess, not a promise, and the cost as the energy you pay for at the price you enter. Fixed fees, parking and idle charges are not included.
Worked example
What does charging a 60 kWh battery from 10 to 80 % cost at 11 kW AC and €0.25 per kWh?
- 60 × (80 − 10) ÷ 100 = 42 kWh into the battery.
- 42 ÷ (1 − 10 %) = 46.67 kWh from the grid.
- 46.67 × €0.25 = €11.67; 46.67 ÷ 11 kW = 4 hr, 15 min.
€11.67, 4 hr, 15 min
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Frequently asked questions
Why is the energy from the grid more than goes into the battery?
Charging loses energy as heat in the charger, cable and battery. Entering your own loss percentage replaces the typical value.
Why does charging slow down after 80 %?
To protect the battery, the car lowers the power as the cells fill up. That is why makers quote 10–80 % times and why the last 20 % takes disproportionately long.
Which battery capacity should I enter?
The usable capacity, not the larger gross figure. It is in the car's specification and is often a few kWh lower than the number in the model name.
Why is my 22 kW wallbox charging at 11 kW?
The car's onboard charger sets the AC limit. Many cars accept 7 or 11 kW, so a faster wallbox cannot go beyond that.
Is DC always more efficient than AC?
Often a little, because the charger does the conversion. But losses depend on the charger, the car and the temperature, so enter your own figure if you know it.
Can I use this for a public charger with a different price?
Yes. Enter that charger's price per kWh. Session or idle fees are not included.
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