Free Electrical calculator

Amps to kVA calculator

Convert current to apparent power in kVA for single-phase or balanced three-phase systems.

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How the calculation works

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

Formula

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

Worked example

ArrangementBalanced three-phase

Current100 A

Voltage400 V

Expected apparent power69.28 kVA

Assumptions and limitations

Assumptions

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

What this does not check

Does not calculate kW without power factor.
Does not assess diversity, starting current or plant sizing.

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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