Reactive Power Calculator

Use real power and power factor values to estimate reactive power change. This is a screening calculation, not capacitor-bank or harmonic-filter selection.

  • Updated August 22, 2026
Inputs
Result

Formulas

  • Current reactive power kVAR = real power kW x tan(arccos(current power factor))
  • Target reactive power kVAR = real power kW x tan(arccos(target power factor))
  • Reactive power reduction kVAR = current reactive power kVAR - target reactive power kVAR

Use this calculator

Estimate current kVAR, target kVAR, and kVAR reduction from kW, current power factor, and target power factor.

Read the result

Review the calculated values with their displayed units and assumptions. The result is a planning aid for the stated inputs, not a final equipment or installation decision.

Check before final work

This is a reactive-power screening estimate. It does not size capacitor banks, evaluate harmonics, check resonance, choose switching equipment, confirm utility approval, or verify equipment ratings.

FAQs

Is kVAR reduction the same as capacitor size?

No. The kVAR reduction is an arithmetic screening value. Actual correction equipment needs harmonic, switching, voltage, utility, and manufacturer review.

Why must target power factor be higher?

This workflow estimates reduction from the current condition to an equal or better target power factor. A lower target would not be a correction reduction.