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ITGlossary · Electrical units
kVA (kilovolt-ampere)
A unit of apparent power equal to 1,000 VA, used to rate UPS systems; real power in kW equals kVA × power factor.
Technical level:Basic
kVA expresses apparent power, that is, the product of voltage and current, without taking into account how much of it is converted into useful work. That is why it is used to rate UPS units, transformers, stabilizers and generators: it defines how much current the device can handle, regardless of the type of load.
Real power in kW is obtained by multiplying kVA by the power factor. A 10 kVA UPS with a factor of 0.9 delivers 9 kW, while with a factor of 1.0 it delivers 10 kW. On a 230 V single-phase supply, 1 kVA corresponds to a current of about 4.3 A.
When comparing quotes, always check the kW as well, not only the kVA. Two UPS units with the same kVA rating can power significantly different real loads.
Related articles
Related terms
- Power FactorThe ratio of real power (W) to apparent power (VA), from 0 to 1, showing how many watts a UPS can deliver per VA.
- Three-phase PowerA supply with three AC phases shifted by 120° (400 V between phases), used for large loads, motors and UPS systems from about 10 kVA.
- C-rateThe charge or discharge current expressed as a multiple of battery capacity, e.g. 1C for a 100 Ah battery means 100 A.
- Charging Power (kW)How much energy flows into the battery per hour, which in AC charging depends on voltage, current and the number of phases.
- Single-phase PowerAn electrical system with one alternating current (AC) voltage phase, commonly used in homes and offices.
- IEC C19/C20 ConnectorsPair of connectors rated up to 16 A under IEC 60320, used on higher-power UPS units, rack PDUs and servers or switches with high-consumption power supplies.