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Enter the battery size, the charge level before and after, and the power of the charger. The car's own charging limit and the charging losses are taken into account, because the slower of the two decides the speed.

Enter your values

Usable battery capacity of the car.
Where do I find this?

It is in the car's manual, the spec sheet or the vehicle settings. Use the usable capacity if both are given.

State of charge when you plug in (0 to 100).
Where do I find this?

Read it from the dashboard or the car's app.

State of charge when you unplug (0 to 100).
Where do I find this?

Fast chargers slow down above about 80 %, so a full 100 % takes much longer than this estimate.

On the wallbox label: 3.7, 7.4, 11 or 22 kW are common for AC.
Where do I find this?

The wallbox or charging point shows its power in kW on its label or in the app. A normal household socket gives about 2.3 kW.

For a charging station, use the power shown on the display.

The onboard charger of the car limits AC charging. Leave empty if you do not know it.
Where do I find this?

The manual or the spec sheet states the maximum AC charging power, often 7.4 or 11 kW. The slower of the charger and the car decides.

Energy lost between the meter and the battery. ADAC measured about 6 to 10 % on an 11 kW wallbox and 13 to 25 % on a household socket.
Where do I find this?

If you do not know it, 10 is a reasonable start.

Result

Enter your values to see the result.

Charging time
– hours
In minutes
– min
Added to the battery
– kWh
Power used
– kW

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How it is calculated

  • Energy added = battery size × (end % − start %) ÷ 100
  • Power used = the smaller of the charger power and the car's limit
  • Charging time (h) = energy added ÷ (1 − losses ÷ 100) ÷ power used

Example

A 60 kWh battery from 20 % to 80 % needs 36 kWh. With 10 % losses that is 40 kWh from the charger. At 11 kW the charge takes 40 ÷ 11 = 3.6 hours.

What this estimate leaves out

Real charging slows down at high charge levels and in the cold, and a fast charger changes its power during the charge. Use this as an estimate for AC charging at home.

Sources: ADAC: charging losses of electric cars, measured (in German)

Written and reviewed by QLines, Cologne · Last reviewed

FAQ

Frequently Asked Questions

How long does it take to charge an electric car?

Divide the energy you need by the charging power. A 60 kWh battery charged from 20 % to 80 % needs 36 kWh; on an 11 kW wallbox with some losses that takes about 3.6 hours.

Why is my car charging slower than the wallbox power?

The onboard charger of the car limits AC charging, often to 7.4 or 11 kW. The slower of the wallbox and the car decides the speed.

How long does it take to charge from a normal socket?

A household socket gives about 2.3 kW and loses more energy: with 15 % losses the same 36 kWh take about 36 ÷ 0.85 ÷ 2.3 ≈ 18 hours.

Does charging to 100 % take longer?

Yes. Charging slows down toward the end to protect the battery, so the last 20 % takes disproportionately long.

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