Electrical
Power Factor Calculator
Calculate power factor and reactive power in kVAR from active power in kW and apparent power in kVA, with a worked power triangle example.
How it works
PF = kW / kVA; kVA² = kW² + kVAR²; kVAR = √(kVA² − kW²)
For 8 kW and 10 kVA, PF = 8 / 10 = 0.8 and reactive power = √(10² − 8²) = 6 kVAR.
The reactive result is a magnitude. The power triangle assumes sinusoidal voltage and current.
FAQ
Why must kW be no greater than kVA?
Active power is the useful component of apparent power, so its magnitude cannot exceed the total. Apparent power must be greater than zero.
Does this tell me leading or lagging?
No. The magnitudes alone do not distinguish capacitive from inductive reactive power.
Can I use this for distorted waveforms?
kW / kVA still describes true power factor, but the simple reactive power triangle does not separate distortion power. This page uses the sinusoidal model.