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Calculation Machine

Power Factor Correction Calculator

Capacitor kVAr needed to fix power factor.

Reviewed by James Whitfield · How we check our maths

Your values

ⓘ Live results

Results
Capacitor size needed
95.3 kVAr
kVA before
208.3
kVA after
157.9
Monthly saving
$403.51

Quick answer

Correction capacitors supply reactive power so the supply only carries real current.

The formula

kVAr = kW × (tanφ1 − tanφ2)

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Real power150 kW
  • Current power factor0.72
  • Target power factor0.95
  • Demand charge per kVA8 $

Result

  • Capacitor size needed95.3 kVAr
  • kVA before208.3
  • kVA after157.9
  • Monthly saving$403.51

How to use the Power Factor Correction Calculator

  1. 1Enter your real power load in kW.
  2. 2Enter current and target power factor.
  3. 3Add the demand charge to see savings.

Frequently asked questions

What target PF should I aim for?

0.95 is the usual utility threshold before penalties.

Can PF be over-corrected?

Yes — leading power factor causes its own problems and penalties.

About this calculator