Power factor correction calculator
Calculate the reactive power to compensate to move from the current power factor to the target, and the capacitor size.
How it is calculated
Qc (kVAR) = P (kW) × (tan φ1 − tan φ2)
C delta = Qc / (3 · ω · V²) C wye = Qc / (ω · V²) ω = 2π·f
Raising the power factor reduces current, cable losses and the apparent power (kVA) that transformers and generators must supply.
Many utilities add demand or reactive charges when the power factor falls below 0.85–0.95.
Frequently asked questions
What power factor do utilities penalise?
It varies: many US utilities penalise below 0.85–0.90; in Europe the threshold is often 0.95.
Fixed or automatic capacitor bank?
Fixed for a steady load such as a motor that always runs the same; automatic, switched in steps, for loads that vary during the day.
What happens if I overcorrect?
The installation turns capacitive, which can cause overvoltage and resonance with harmonics.