How to use this EV charging calculator
- Battery capacity, enter your car's usable battery size in kilowatt-hours (kWh).
- Charger power, enter the output of your charger in kilowatts (kW), such as 7.4 for a typical home wallbox.
- Current and target charge, set the percentage you are starting from and the level you want to reach.
- Electricity rate, enter your price per kWh, and adjust the charging efficiency if you want a tighter estimate.
- Read the energy added, charging time and cost, they update instantly as you type.
Nothing is submitted or stored: the numbers never leave your device, so you can compare chargers and tariffs privately.
How EV charging time is calculated
The starting point is the energy your battery needs. That is your battery capacity multiplied by the gap between your target and current charge: energy needed = battery kWh × (target% − start%). So a 60 kWh battery going from 20% to 80% needs 60 × 0.60 = 36 kWh stored in the pack.
Charging is never perfectly efficient, some energy is lost as heat in the cable, charger and battery. To account for this the calculator divides the battery energy by a charging efficiency of about 0.9, giving the energy actually drawn from the supply. Time = grid energy ÷ charger kW, andcost = grid energy × your rate. The charger power is the limiting factor: Level 1 trickle charging runs at roughly 1.4 kW, Level 2 home and public chargers at about 7 to 11 kW, and DC fast chargers at 50 kW or more for rapid top-ups.
Estimate only: Real charging speed tapers off above roughly 80% and varies with temperature, battery state and charger limits, so treat these figures as a close planning estimate rather than an exact time.
Charger levels at a glance
- Level 1 (around 1.4 kW): a standard household outlet, slow but fine for overnight top-ups.
- Level 2 (around 7-11 kW): home wallboxes and most public chargers, the everyday choice.
- DC fast (50 kW and above): rapid charging for long trips, best used between roughly 20% and 80%.
Frequently asked questions
How long does it take to charge an electric car?
It depends on the battery size, the charger power and how much charge you need to add. A 60 kWh car going from 20% to 80% adds about 36 kWh, which is around 5 to 6 hours on a 7.4 kW home charger and under an hour on a 50 kW DC fast charger.
How much does it cost to charge at home?
Multiply the energy you add by your electricity rate. Adding 36 kWh at $0.17 per kWh costs about $6.10, a little more once charging losses are included.
Why is the time longer than battery size ÷ charger?
Charging loses some energy as heat, so a typical efficiency is about 90%. This tool divides by that efficiency, which makes the estimate a touch longer and more realistic.
Is my data uploaded?
No, everything is calculated on your device and nothing is sent anywhere.