⚡ kVA Calculator
Calculate apparent power (kVA) for single-phase or three-phase circuits from voltage and current.
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Calculating kVA
Apparent power (kVA) is the total power flowing in an AC circuit, combining both the real (working) power and reactive power. For a single-phase system, kVA = (V × I) / 1000. For a three-phase system, kVA = (√3 × V × I) / 1000, where V is the line-to-line voltage and I is the line current, with the √3 factor accounting for the phase relationships across three conductors.
kVA is used for sizing transformers, generators, and UPS systems, since these devices are limited by total current-carrying capacity regardless of how much of that power is real versus reactive. Multiplying kVA by the power factor gives the real power in kW.
Last reviewed August 2026