Power Factor Correction Calculator
Enter real power in W, kW, or MW and two decimal lagging power factors to calculate Qc = P × [tan(acos(PF₁)) − tan(acos(PF₂))].
A QUICK WALKTHROUGH
How to use this tool
- Enter positive real power and select its unit.
- Enter initial and target lagging power factors; target must be at least initial.
- Calculate initial reactive power, target reactive power, and their difference.
Inputs and units
Real power must be finite, positive, and no more than 10¹² W after conversion. Each power factor is a decimal from 0.000001 to 1. W produces var, kW produces kvar, and MW produces Mvar.
Calculation boundary
This ideal calculation assumes positive real power, lagging power factors, and unchanged real power. It does not model leading power factors, harmonics, or changing loads. It does not select capacitor banks or equipment, or provide installation or electrical-safety advice.
GOOD TO KNOW
Common questions
Should I enter 80 or 0.8?
Enter 0.8 for a power factor of 80%. Percent inputs are not accepted.
Can the target equal the initial power factor?
Yes. The calculated reduction is zero. A target below the initial value is outside this improvement calculation.
Does the result size equipment?
No. It is only a mathematical reactive-power difference. All calculation runs locally in the browser.