EV Charging Time Calculator
Hours to charge from any state of charge, at any power.
Enter your values
Enter the battery capacity in kWh.
Enter the starting charge in %.
Enter the target charge in %.
Enter the charger power in kW.
Enter the charging efficiency in %.
Enter the efficiency in mi/kWh.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Charging time
- 4 h 33 min
- Energy added
- 45 kWh
- Grid energy drawn
- 50 kWh
- Range gained
- 158 mi
- Average rate
- 35 mi of range per hour
Quick answer
Charging time = energy needed ÷ (charger power × efficiency), where energy needed is battery capacity × the change in state of charge.
Hours = kWh needed ÷ (kW × efficiency)
At a glance
| What it does | Hours to charge from any state of charge, at any power. |
|---|---|
| Category | Auto |
| Inputs needed | Battery capacity, Starting charge, Target charge, Charger power, Charging efficiency, Efficiency |
| Main output | Charging time |
| Formula | Hours = kWh needed ÷ (kW × efficiency) |
| Cost | Free — no sign-up, no download |
How to use the EV Charging Time Calculator
- 1Enter your usable battery capacity in kWh.
- 2Set the starting and target state of charge.
- 3Enter the charger's real output — 7.4 kW home, 11–22 kW AC, 50–350 kW DC.
Inputs explained
- Battery capacity(kWh)
- Enter the battery capacity in kWh.
- Starting charge(%)
- Enter the starting charge in %.
- Target charge(%)
- Enter the target charge in %.
- Charger power(kW)
- Enter the charger power in kW.
- Charging efficiency(%)
- Enter the charging efficiency in %.
- Efficiency(mi/kWh)
- Enter the efficiency in mi/kWh.
Worked example
Using the values the calculator loads with:
Inputs
- Battery capacity75 kWh
- Starting charge20 %
- Target charge80 %
- Charger power11 kW
- Charging efficiency90 %
- Efficiency3.5 mi/kWh
Results
- Charging time4 h 33 min
- Energy added45 kWh
- Grid energy drawn50 kWh
- Range gained158 mi
- Average rate35 mi of range per hour
Frequently asked questions
Why stop at 80%?
DC fast charging tapers sharply above 80% to protect the cells, so the last 20% can take as long as the first 60%.
Does cold weather slow charging?
Yes. A cold pack limits charge current until it warms, which is why many EVs precondition the battery on the way to a fast charger.
What do I need to enter into the EV Charging Time Calculator?
Just 6 values: battery capacity, starting charge, target charge, charger power, charging efficiency, efficiency. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the EV Charging Time Calculator work out the answer?
Charging time = energy needed ÷ (charger power × efficiency), where energy needed is battery capacity × the change in state of charge. It applies the formula Hours = kWh needed ÷ (kW × efficiency) and shows the working so you can check each step by hand.
Is the EV Charging Time Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.