Power Factor Calculator
Find power factor from nonnegative real power and reactive power magnitude for sinusoidal AC.
Formula
S = √(P² + Q²); PF = P/S.
Real power P: 300 W · Apparent power ≈ sqrt((300 W)^2+(400)^2) · Power factor ≈ (300 W)÷(500)
How to use
- Enter nonnegative real power P.
- Enter the magnitude of reactive power Q in var.
- Read PF and apparent power.
Examples
- 300 W and 400 var give PF = 0.6 and 500 VA.
Frequently asked questions
What does PF mean?
It is real power divided by apparent power, from 0 to 1 for consuming loads.
Does this cover harmonics?
No. P² + Q² = S² here assumes sinusoidal operation.
Does the result show leading or lagging?
No. Q is entered as a magnitude; its sign is not determined.
Can both powers be zero?
No. With P = Q = 0, apparent power is zero and PF is undefined.
Sources
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