Reactive Power Compensation Calculator

Summary

Enter load power, current power factor, and target power factor to find the required capacitor bank size in kVAR.

How it works

1. Enter the active load power in kilowatts (kW) — the real power drawn by your equipment.
2. Enter the existing power factor (0.01–0.99) — check your utility bill or use a power meter.
3. Enter the target power factor (must be higher than existing, up to 0.99 or 1.0).
4. Enter system voltage (line-to-line for three-phase) and frequency (50 or 60 Hz).
5. The calculator applies Q_c = P × (tan(arccos(PF1)) − tan(arccos(PF2))) to find the kVAR needed.
6. Capacitance per phase is derived from C = Q_c / (2π × f × V²) for three-phase delta, or adjusted for star connection.

Use cases

• Size capacitor banks for industrial motor loads with poor power factor.
• Estimate penalty avoidance savings when correcting power factor above utility thresholds.
• Plan reactive compensation for transformer and generator systems.
• Verify contractor-proposed kVAR bank size against your measured load data.
• Calculate individual capacitor values for single-phase correction circuits.
• Determine staged compensation requirements across multiple load shifts.

Frequently Asked Questions