Three-Phase Power Calculator

Three-phase is the workhorse of commercial and industrial power. Turning a measured current back into real power — or sizing current for a known kW — needs the 1.732 factor that three conductors introduce.

Three-Phase Power Calculator computes kW, kVA and kVAr from voltage and current at any power factor, showing the formula live and switching cleanly to single-phase when needed.

Everything runs in the browser; nothing is uploaded.

• Three-phase and single-phase: Phase count selector.
• Full power set: kW, kVA and kVAr reported together.
• Power factor: Applies your load pf to the power triangle.
• Live formula: sqrt(3) x V x I x pf updated as you type.
• Reverse help: Current needed for a target kW.
• Export: Copy or download as text, CSV or JSON.
• Learning guide: Where 1.732 comes from in practice.

1. Enter the line-to-line voltage (e.g. 400 V).
2. Enter the line current per phase in amps.
3. Set the power factor of the load.
4. Select the phase count — three or single.
5. Read kW, kVA and kVAr for the circuit.
6. Export the measurement if needed.

Example 1 — Motor. 400 V, 30 A, pf 0.85: 17.7 kW, 20.8 kVA.

Example 2 — Heater. 400 V, 43 A, pf 1: 29.8 kW pure resistive.

Example 3 — Low pf. 400 V, 30 A at 0.6 pf: only 12.5 kW for the same current — the case for correction.

Example 4 — Single-phase. A 230 V circuit at 16 A, pf 0.95: 3.5 kW.

• Honest motor math: kW of work vs kVA the cable carries, both visible.
• Phase aware: 1.732 applied exactly where it belongs.
• Explained formula: The calculation shown step by step.
• Export ready: Text, CSV and JSON for records.
• Free and private: No uploads, no accounts, no logging.