Tool
Three-Phase Power Calculator for Engineers & Technicians
Enter a line-to-line voltage and one known value to calculate current, real power (kW), apparent power (kVA) and reactive power (kVAR) for a balanced three-phase load.
Last reviewed · Published by Essential Systems
Results
- Current
- 100 A
- Real power
- 74.8 kW
- Apparent power
- 83.1 kVA
- Reactive power
- 36.2 kVAR
Estimates for balanced loads. Not a substitute for NEC conductor sizing tables or motor nameplate/NEC Table 430.250 values.
Formulas used
- kVA = √3 × V × I ÷ 1,000
- kW = √3 × V × I × PF ÷ 1,000
- I from kW = kW × 1,000 ÷ (√3 × V × PF)
- I from hp = hp × 746 ÷ (√3 × V × PF × efficiency)
- kVAR = √(kVA² − kW²)
Worked example
A 480 V load drawing 100 A at 0.9 PF: kVA = 1.732 × 480 × 100 ÷ 1,000 ≈ 83.1 kVA; kW ≈ 83.1 × 0.9 ≈ 74.8 kW.
Related
Use these results with the Equipment Guide, Generator Sizing and VFD selection guides.
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