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EV calculator

EV Charging Time Calculator

Estimate idealised EV charging time from the charge range and charger power you enter.

Use this calculator

Enter a charge session and charger power.

What your result means

This is an idealised constant-power estimate. Rapid charging may slow as charge rises, and vehicle or charger limits can reduce actual power.

Worked example

A 20%–80% charge of a 60 kWh battery at 7 kW:

Energy added
36 kWh
Ideal time
5h 9m

Actual DC rapid charging can taper substantially.

Formula

Battery energy addedCharger power\frac{\text{Battery energy added}}{\text{Charger power}}

How charger power changes the ideal charging time

More charger power reduces the ideal charging time, but the relationship shown here assumes that the stated power is delivered continuously.

Real charging is more complicated. The vehicle can limit how much power it accepts, and rapid DC charging normally does not remain at its peak rate throughout the session. Charging can slow significantly as the battery fills.

Charger powerIdeal time
2.3 kW15h 39m
3.6 kW10h 0m
7 kW5h 9m
11 kW3h 16m
22 kW1h 38m
50 kW0h 43m
100 kW0h 22m
150 kW0h 14m
250 kW0h 9m
350 kW0h 6m

Why real EV charging time can be longer

The number printed on a charger is not necessarily the power your vehicle will receive for the whole session.

Actual charging speed can be affected by the vehicle's maximum AC or DC charging rate, battery temperature, state of charge and the charging curve. Rapid charging commonly slows as the battery approaches a high state of charge.

The result should therefore be read as an ideal constant-power calculation, not a guaranteed charging time.

Assumptions and limitations

  • Constant charger power is assumed; losses and charging curves are excluded.

Helpful questions

How is EV charging time calculated?

The calculator divides the ideal battery energy required by the charger power entered.

Why does my car charge slower than the charger rating?

The vehicle may accept less power than the charger can provide, and charging power can change during the session.

Why does rapid charging slow down near a full battery?

EV battery-management systems can reduce charging power at higher states of charge. The calculator does not model a vehicle-specific charging curve.

Can a 150 kW charger always give my car 150 kW?

No. The vehicle, battery conditions and charger can all limit actual power.

Does this calculator include charging losses?

No. It uses ideal battery energy and constant charger power.

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