Free Electrical calculator

Amps to kW calculator

Convert current to real power in kW for single-phase or balanced three-phase systems using voltage and power factor.

Enter the project values

All values remain in your browser. Review the assumptions before using the result.

Your result will appear here.Calculate to see the outputs, formula and substituted working.

How the calculation works

Real-power relationship for single-phase or balanced three-phase systems.

Formula

P = V × I × PF (1Φ) or P = √3 × VLL × I × PF (3Φ)

Worked example

ArrangementBalanced three-phase

Current32 A

Voltage400 V

Power factor0.90

Expected power19.95 kW

Assumptions and limitations

Assumptions

Voltage and current are RMS values.
Three-phase values represent a balanced load.

What this does not check

Does not infer power factor or equipment efficiency.
Does not assess demand, harmonics, cables or protection.

Formula version: 1.0 · Last reviewed: 16 August 2026

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Engineering basis: first-principles electrical relationships using user-entered values. The page does not reproduce BS 7671 tables or establish compliance. Complete the project-specific design against the current BS 7671 information, manufacturer data and the applicable project requirements.

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