Calculator
kW to Amps Calculator
Change the inputs to match your equipment. Results update automatically.
Formula
Üç faz: I = P × 1000 / (√3 × U × cos φ)Tek faz: I = P × 1000 / (U × cos φ) Worked example
For 15 kW electrical input power, 400 V line-to-line voltage and power factor 0.85: I = 15000/(√3 × 400 × 0.85) = 25.47 A. This does not represent a motor with 15 kW shaft output.
What the formula assumes
For three phases, the load is balanced and the waveforms are sinusoidal. Voltage is line-to-line and current is line current. For one phase, voltage is measured across the load. Unbalanced or distorted waveforms need appropriate power measurements.
Motor shaft power is different
Motor nameplate kW normally refers to mechanical output. Electrical input is shaft output divided by efficiency. A 15 kW shaft output at 90% efficiency requires about 16.67 kW input. At 400 V and power factor 0.85, current is about 28.30 A rather than 25.47 A.