Three Phase Power Calculator
Calculate three phase power, current or voltage from load and power factor with this free electrical engineering calculator in your browser.
Enter Values
Minimum 0
Minimum 0
Range 0–1
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter line voltage, line current and power factor.
- Read the kW and kVA.
How it works
P (kW) = √3 × line voltage × line current × power factor; kVA drops the power factor.
Worked example
415 V, 20 A, 0.85 PF. ≈ 12.2 kW (14.4 kVA).
Common mistakes
- Using phase voltage where line voltage is required.
- Forgetting the √3 factor for three-phase.
Frequently asked questions
What is the three-phase power formula?
P = √3 × line voltage × line current × power factor. For 415 V, 20 A at 0.9 PF that is about 12.9 kW.
Why the √3 factor?
It comes from the 120° phase spacing between the three lines, which relates line and phase quantities in a balanced system.
Single vs three phase?
Single-phase power is V × I × PF; three-phase adds the √3 factor for the three line conductors.
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Cite this tool
Zerdly. (2026). Three Phase Power Calculator. Retrieved from https://www.zerdly.com/tools/three-phase-power-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.