3-Phase Power Calculator (kVA · kW · Amps)
Calculate three-phase apparent power (kVA), real power (kW), reactive power (kVAR), and current (amps) from voltage, current, or power factor inputs.
Results
What is it?
In three-phase AC systems: kVA = √3 × VL × IL / 1000 (apparent power). Real power kW = kVA × PF. Reactive power kVAR = √(kVA² − kW²). These relationships form the power triangle. Power factor (PF) is the ratio of real to apparent power — unity PF means all power does useful work.
How to use
Select the calculation direction. For a generator or motor nameplate problem, use "kW & PF → kVA & Amps" to find the kVA rating needed. For measuring an existing load with a clamp meter, use "Voltage & Current → Power".
Example scenario
A 415 V three-phase motor draws 100 A at PF = 0.85. kVA = 1.732 × 415 × 100 / 1000 = 71.9 kVA. Real power = 71.9 × 0.85 = 61.1 kW. Reactive = √(71.9² − 61.1²) = 37.8 kVAR.
Pro tip
Utilities charge for low power factor (below 0.9 or 0.95 depending on jurisdiction) because reactive current loads the distribution system. Adding capacitor banks to bring PF above 0.95 is a common energy-saving measure. Use the kVAR output to size the correction capacitors.