EV Charging Time Calculator
Calculate how long it takes to charge your electric car, based on battery capacity, charge level and the power of the charger.
How to use the EV charging time calculator
- Enter the battery capacity of the electric car in kWh.
- Enter the charge level you're starting from and the charge level you want to reach.
- Enter the power of the charger in kW — the calculator automatically factors in typical charging loss and shows the charging time in hours and minutes.
How the charging time is calculated
First the calculator finds how much energy needs to be charged, then divides this by the effective charging power:
Charging time (h) = Energy ÷ (Charging power × 0.9)
The factor 0.9 represents typical charging efficiency — some energy is lost as heat during charging. With a 64 kWh battery, charging from 20% to 80% and an 11 kW charger, the charging time is 38.4 ÷ (11 × 0.9) ≈ 3 hours and 53 minutes.
The charging curve — why the last percent takes longest
An electric car does not charge at a constant power from empty to full. At a low state of charge the battery can accept high power, but as it fills, the car tapers the power down to protect the cells from heat and wear. This taper is why rapid charging from ten to eighty percent can take half an hour, while the last twenty percent alone takes just as long.
Manufacturers therefore quote charging time for an interval rather than to a hundred percent. On a long trip it usually pays to charge briefly and more often within the fast range rather than filling all the way up. Cold pulls the same way: a cold battery accepts less power, which is why some cars preheat the battery automatically when a rapid charger is set as the destination.
Frequently asked questions
Why does the calculator use 90% charging efficiency?
During charging, some energy is lost as heat in the cable, charger and battery. An efficiency of around 90% is a common average for home and standard charging, though it varies somewhat between cars and chargers.
Why does fast charging slow down toward the end?
Most EVs taper the charging power as the battery approaches full, often starting around 80%, to protect the battery cells. That's why the last 20% often takes about as long as the first 60%.
What's the difference between home charging and fast charging?
Home charging normally uses 2.3–11 kW AC power and takes several hours, while fast chargers deliver 50–350 kW DC power and can charge a large share of the battery in 20–40 minutes.