How this calculator works
Apparent power combines RMS voltage and current and describes the loading of supply equipment. Real power is the apparent power multiplied by total power factor. Balanced three-phase formulas use either line-to-line voltage with sqrt(3) or line-to-neutral voltage with 3. Volt-amperes and watts share dimensions but describe different quantities, so both labels are retained explicitly.
Formula
S = k Vrms Irms in VA; kVA = S/1000; P = S PF. k = 1, sqrt(3), or 3 for the selected supply reference.
Worked example
A single-phase 230 V, 10 A load has S = 2300 VA = 2.3 kVA. At power factor 0.8 it consumes 1840 W. Three phases at 100 V line-to-neutral and 2 A give 600 VA.
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Frequently asked questions
Is kVA equal to kW?
Only at unity power factor. Multiply kVA by power factor to obtain kW.
Which current should I enter?
Use RMS line current. The three-phase model assumes equal loading on all phases.
Why retain VA rather than a watt selector?
Apparent power and real power have different electrical meanings even though both reduce to the same SI dimensions.