Level 2 EV charger kW and current calculator

Preliminary estimate

Inputs

Calculation note

Power-current conversion uses nominal single-phase voltage. It does not size the circuit or service.

Method

kW = volts x amps / 1000

A = kW x 1000 / volts

Session energy kWh = charger kW x session hours

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Formula variables

  • Volts is the selected nominal supply voltage.
  • Amps is the EVSE output or nameplate current entered by the user.
  • Charging kW is the calculated or entered AC charging power.
  • Session hours is optional time used to estimate delivered AC energy.

Assumptions

  • Level 2 charging power is estimated with single-phase AC power arithmetic.
  • Voltage is treated as nominal; common Canadian references include 208 V and 240 V.
  • Session energy is calculated from charger kW and entered session hours before vehicle losses or charge taper.
  • This calculator does not size an EV circuit, branch breaker, conductor, receptacle, EVEMS, or service capacity.

Examples

40 A at 240 V. A 40 A Level 2 EVSE at 240 V estimates 9.6 kW. Over a 6 hour session, that is 57.6 kWh before vehicle losses.

208 V commercial supply. At the same current, 208 V supplies less charging kW than 240 V, so charging-time estimates should use the actual nominal supply.