Home EV charging schedule planner
Set your departure time and the charge you need. The planner works backwards to show the latest estimated start time, while respecting both the charger's power and your car's AC charging limit.
On the departure day
How this is calculated
Energy to add = battery capacity × the change in state of charge. Moving a 60 kWh battery from 20% to 80% adds 36 kWh to the battery.
Effective AC power is the lower of the charger power and the car's onboard-charger limit. A 22 kW wallbox still supplies only 11 kW to a car that accepts 11 kW AC.
Time = battery energy to add ÷ (effective power × efficiency). The latest start is that duration subtracted from your departure time.
The wall-energy result divides battery energy by the chosen efficiency. It is the better figure to use when estimating the electricity bought for the session.
Assumptions and limits
- This is an AC planning estimate. It assumes the selected power remains available throughout the session and the vehicle starts when requested.
- A tariff's cheap period is not enforced by the calculator. Compare the start time with your tariff window and start earlier if the session will not fit.
- Cars can delay, pause or reduce charging because of temperature, battery conditioning, load management or a configured schedule. Leave a buffer when being ready is important.
- The everyday charge target is vehicle-specific. Use the recommendation shown by your car or in its current manual rather than assuming one percentage suits every battery.
Frequently asked questions
Should I schedule charging to start or to finish at a time?
If your car or wallbox supports a ready-by time, that is often the simplest option because the system can calculate its own start. Otherwise, use this planner's latest-start estimate and add a buffer.
Why could the real finish time be later?
Available power can be reduced by the car, a dynamic load-balancing system, temperature or other site loads. Charging may also slow near a high target state of charge.
Can I use this for DC fast charging?
No. DC charging power changes along a vehicle-specific charging curve. This tool is for the steadier AC charging normally used at home or work.
Does starting later always make electricity cheaper?
No. Savings depend on your actual tariff and whether the whole session fits into its cheaper period. Include fixed fees and any peak-rate energy when comparing plans.
