About the EV Charging Time Calculator
This EV charging time calculator estimates how long it takes to charge an electric vehicle from one state of charge to another. Enter the battery’s usable capacity, the starting and target percentage, and the charger you will use — a regular 120 V outlet, a Level 2 home or public charger, or a DC fast charger — and it returns the charging time, the energy added and the miles of range gained.
The real charging speed is limited by whichever is slower: the charger or the car. On AC (Level 1 and Level 2) the car’s onboard charger sets the cap, often 7–11.5 kW. On DC fast chargers the car’s maximum DC charge rate is the limit. The calculator applies both, plus a charging-efficiency factor for energy lost as heat.
DC fast charging slows sharply as the battery fills, so the calculator assumes full power up to 80% and about one-third of that power from 80% to 100%. Real charging curves vary by model, battery temperature and charger, so treat the result as a planning estimate — it is usually quickest on road trips to stop at 80%.
With the default inputs, the charging time is 4h 32m 44s. Change any value above to recalculate instantly.
How to use the ev charging time calculator
- 1Enter your EV’s usable battery capacity in kWh.
- 2Set the starting and target state of charge.
- 3Choose the charger type, or enter a custom power rating.
- 4Enter your car’s onboard AC charger limit and maximum DC charging rate.
- 5Read the charging time and compare charger types in the chart.
Formula and method
The energy to add is the usable battery capacity multiplied by the change in state of charge. The effective charging power is the lower of the charger’s rating and the car’s limit — the onboard charger for AC charging or the maximum DC rate for fast charging — multiplied by charging efficiency to account for heat losses. Time is energy divided by effective power.
For DC fast charging, energy added above 80% state of charge is assumed to flow at one-third of the effective power, a simple approximation of the taper every EV applies to protect the battery. Range added is energy added × the vehicle’s miles per kWh.
- Battery
- Usable battery capacity (kWh)
- Start, Target
- State of charge as a fraction
- Car limit
- Onboard AC charger or max DC rate (kW)
- Efficiency
- Share of charger energy stored in the battery
Worked examples
75 kWh battery, 20% to 80% on a 48 A Level 2 charger
Adding 60% of 75 kWh is 45 kWh. The 11.5 kW charger is capped by the car’s 11 kW onboard charger, and at 90% efficiency 9.9 kW reaches the battery, so the session takes about 4 hours 33 minutes and adds roughly 158 miles.
Level 1 wall outlet, 60 kWh battery
A 120 V outlet delivers about 1.26 kW to the battery after losses, so adding 30 kWh takes almost 24 hours — only about 5 miles of range per hour.
DC fast charging 10% to 90%
At 138 kW effective, 10–80% (56 kWh) takes about 24 minutes, but the last 8 kWh from 80–90% runs at one-third power and adds another 10 minutes, for a total of roughly 35 minutes.
250 kW charger limited by the car
The car only accepts 150 kW, so a 250 kW charger is no faster than a 150 kW one: 56 kWh at 138 kW effective takes about 24 minutes.
Frequently asked questions
How long does it take to charge an electric car?+
It depends on battery size and charger. A Level 1 outlet can take a day or more for a full charge, a Level 2 home charger typically 6–10 hours for most EVs, and a DC fast charger about 20–40 minutes to go from 10% to 80%.
Why does charging slow down after 80%?+
As a lithium-ion battery fills, the car’s battery management system reduces current to prevent overheating and cell damage. On fast chargers the last 20% can take as long as the first 60%, which is why road-trip planners usually charge to about 80%.
Will a more powerful Level 2 charger charge my car faster?+
Only up to your car’s onboard charger limit. If your car accepts 7.7 kW, an 11.5 kW wall box will not speed things up. Check your car’s AC charging rating before paying for a higher-amperage circuit.
Is it bad to charge an EV to 100% every day?+
Many manufacturers recommend setting a daily limit around 80–90% for nickel-based batteries and charging to 100% only before long trips, because sitting at full charge accelerates wear. Some LFP batteries are designed to be charged to 100% regularly — follow your owner’s manual.