Current from electrical input power
Calculate current from active electrical input power in watts, voltage and power factor. Choose single phase or a balanced three-phase system. For three phase, enter line-to-line voltage.
Calculator: illustrative inputs — Current from electrical input power
Formula and worked examples
I1 = P / (V × PF); I3 = P / (√3 × Vline-line × PF)
For single phase, 2300 W, 230 V and PF = 1 give 10 A. For balanced three phase, 10000 W, 400 V and PF = 0.8 give about 18.04 A. Enter watts: 10 kW is 10000 W. If a rating is mechanical output, first derive electrical input using the applicable efficiency; do not treat the output rating as electrical input.
Scope of the result
The formulas describe steady active-power relationships. They do not include starting current, unbalance or harmonics and do not select a cable, breaker or protective device. Power factor must be above zero and no greater than one. Use the actual supply and equipment data.