Power factor correction kVAR calculator

Preliminary estimate

Inputs

Calculation note

kVAR is estimated from the tangent difference between existing and target power factor angles.

Method

kVAR = kW x (tan(arccos existing PF) - tan(arccos target PF))

kVA = kW / PF

3-phase A = kVA x 1000 / (sqrt(3) x V)

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Formula variables

  • kW is the real load used for the correction estimate.
  • Existing PF is the present power factor before correction.
  • Target PF is the desired corrected power factor.
  • V is the selected nominal system voltage for current comparison.

Assumptions

  • The calculation uses real load in kW and the tangent difference between existing and target power factor angles.
  • Current reduction is shown for the selected voltage and phase as a planning estimate.
  • Capacitor staging, harmonics, switching transients, utility metering, and over-correction are not evaluated.
  • Use utility bills, measurements, equipment data, and qualified engineering review before selecting correction equipment.

Examples

600 V commercial load. A 150 kW load improved from 0.78 PF to 0.95 PF requires about 71.04 kVAR and reduces estimated 600 V three-phase current by about 33.11 A.

Utility-bill workflow. Use measured demand and billing power factor when available. This worksheet gives the arithmetic target before equipment-specific review.