Three Phase Power Calculator
Enter line voltage, current, and power factor to instantly calculate apparent, active, and reactive three-phase power.
System Parameters
Common values: 208 V, 415 V, 480 V, 690 V
Leave blank to skip shaft/output power estimate
Power Results
Enter values on the left and click Calculate.
Apparent Power (S)
S = √3 × V × I
—
kVA
Active Power (P)
P = S × cos φ
—
kW
Reactive Power (Q)
Q = S × sin φ
—
kVAR
Output / Shaft Power
P_out = P × η
—
kW
Phase Angle (φ)
—
Power Factor Type
—Power Triangle Reference
S
Apparent (kVA)
√(P² + Q²)
P
Active (kW)
S × cos φ
Q
Reactive (kVAR)
S × sin φ
Summary
Enter line voltage, current, and power factor to instantly calculate apparent, active, and reactive three-phase power.
How it works
- Enter the line-to-line voltage in volts (e.g. 415 V for a standard industrial supply).
- Enter the line current in amperes drawn by the load.
- Enter the power factor as a decimal between 0 and 1 (e.g. 0.85).
- Select lagging or leading to indicate whether the load is inductive or capacitive.
- The calculator instantly computes apparent power (kVA), active power (kW), and reactive power (kVAR).
- Results update in real time as you change any input.
Use cases
- Size generators, transformers, and switchgear for industrial installations.
- Verify that a motor drive or UPS system meets load requirements.
- Calculate power factor correction capacitor sizing.
- Estimate electricity costs based on active power consumption.
- Cross-check nameplate data on three-phase motors and panels.
- Educational use — visualize the power triangle relationship.
- Quick field calculations during commissioning or maintenance.
- Convert between apparent, active, and reactive power quantities.
Frequently Asked Questions
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Last updated: 2026-05-23 ·
Reviewed by Nham Vu