Power factor after a partial capacitor bank calculator

Power factor after compensation is calculated as P / sqrt(P² + [P × sqrt(1−PF1²)/PF1 − Q_C]²). Use the stated system boundary and matching input units.

\mathrm{PF}_{2} = \frac{P}{\sqrt{P^{2} + \left(\frac{P \times \sqrt{1 - \mathrm{PF}_{1}^{2}}}{\mathrm{PF}_{1}} - Q_{C}\right)^{2}}}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

Worked example

Given

$P$ = 100 kW
$\mathrm{PF}_{1}$ = 0.8 —
$Q_{C}$ = 20 kVAR

\mathrm{PF}_{2} = \frac{100}{\sqrt{{100}^{2} + \left(\frac{100 \times \sqrt{1 - {0.8}^{2}}}{0.8} - 20\right)^{2}}} \approx 0.8762

Symbols and units

Symbol	Meaning	Unit
$\mathrm{PF}_{2}$	power factor after compensation	—
$P$	unchanged real input	kW
$\mathrm{PF}_{1}$	initial power factor	—
$Q_{C}$	operating capacitor capacity	kVAR

Related calculators

Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.