Enter Values
Formula
For balanced three-phase power:
kW = √3 × V × A × PF ÷ 1000
kVA = √3 × V × A ÷ 1000
Where:
- V = line-to-line voltage
- A = current in amps
- PF = power factor
- √3 ≈ 1.732
Examples
Example 1
480 V, 100 A, PF = 0.90
kW = 1.732 × 480 × 100 × 0.90 ÷ 1000
kW = 74.82 kW
kVA = 1.732 × 480 × 100 ÷ 1000
kVA = 83.14 kVA
Example 2
0.48 kV, 0.10 kA, PF = 0.85
kW = 1.732 × 480 × 100 × 0.85 ÷ 1000
kW = 70.67 kW
Example 3
600 V, 55 A, PF = 0.92
kW = 1.732 × 600 × 55 × 0.92 ÷ 1000
kW = 52.59 kW
Using the Correct Values
- Voltage: enter RMS line-to-line voltage, not line-to-neutral voltage.
- Current: enter RMS line current for the balanced load.
- Power factor: use the load's actual power factor when available.
The square-root-of-three multiplier is appropriate when line-to-line voltage and line current are used for a balanced three-phase system.
Assumptions and Limitations
This calculation assumes a balanced sinusoidal load. It does not separately model phase imbalance, harmonics, neutral current, voltage distortion, demand, motor efficiency, or transient starting current.
Do not use calculated running kW or kVA alone to size motor circuits, generators, transformers, conductors, or overcurrent protection.