EV Charging Time Calculator
Estimate how long an electric car takes to charge at home or at a rapid charger, then compare the ideal time with a more realistic estimate allowing for charging losses, vehicle limits and tapering.
Why rapid charging slows as the battery fills
The charger’s headline kW rating is only its maximum capability. The vehicle controls how much power it accepts, and the rate usually changes throughout a DC charging session. It commonly falls at a higher state of charge to protect the battery.
Ideal versus realistic time
The ideal figure assumes the effective maximum power continues throughout. The tapered estimate applies a reduction above the selected threshold, giving a more useful planning comparison.
Why two cars differ on one charger
Battery temperature, voltage architecture, charging curve and starting percentage can cause different speeds even when both cars use the same rapid charger.
How EV charging time is calculated
First calculate the energy needed at the battery: usable battery capacity × (target percentage − starting percentage). Allow for charging losses, then divide by the lower of the charger output and the vehicle’s maximum charging rate. The realistic result also reduces the assumed rate above 80% to illustrate rapid-charging taper.
Example: moving a 60 kWh usable battery from 20% to 80% adds 36 kWh at the battery. A simple calculation on a 7.4 kW home charger is just under five hours before losses. With 10% losses, the planning estimate is roughly 5 hours 21 minutes.
Common UK EV charging speeds
Home and destination AC
A UK three-pin socket is commonly treated as about 2.3 kW, while a dedicated single-phase home charger is usually around 7 kW or 7.4 kW. Some cars and three-phase locations support 11 kW or 22 kW AC.
Rapid and ultra-rapid DC
Public rapid chargers commonly advertise 50 kW or more, with ultra-rapid units reaching 150–350 kW. Your car may accept much less than the charger’s headline rate, and peak power is not normally sustained for the whole session.
EV charging time questions
Why does a 150 kW charger not always deliver 150 kW?
The car requests the power it can safely accept. Battery temperature, state of charge, the vehicle’s charging curve and shared charger capacity can all reduce the actual rate.
Why is charging from 80% to 100% slower?
Most EVs progressively reduce DC charging power as the battery fills. On a long journey, stopping near 80% and continuing to another charger can therefore be quicker than waiting for 100%.
Should I enter gross or usable battery capacity?
Use the usable battery figure where possible. Manufacturers may reserve part of the gross capacity to protect the battery, so using gross capacity can overstate the energy you can add.
Is this accurate for home charging?
Home AC charging is usually steadier than rapid DC charging, so the simple estimate can be close, but the vehicle’s AC limit, losses, temperature and power-management settings still matter.
To see whether home charging finishes before an off-peak tariff ends, use the cheap-rate window calculator.