KVA Calculator
Calculate kilovolt-amperes (KVA) for single-phase and three-phase electrical systems from voltage and current.
Volts
Amps
PF
0.8-0.95 typical, 1.0 for resistive loadsResults
—KVA
KW (Real Power)—
KVAR (Reactive)—
Watts—
Power Factor—
Formula Used
KVA = (V × A) ÷ 1000
What Is KVA?
KVA (kilovolt-amperes) is the unit of apparent power in an electrical circuit. Apparent power combines real power (kilowatts, KW) and reactive power (kilovolt-amperes reactive, KVAR). Generators, transformers, and UPS systems are rated in KVA because they must handle both components.
KVA Formulas
Single Phase
KVA = (Volts × Amps) ÷ 1,000
Three Phase
KVA = (Volts × Amps × √3) ÷ 1,000
KW from KVA
KW = KVA × Power Factor
Common Generator Sizes
| KVA Rating | KW (at 0.8 PF) | Typical Use |
|---|---|---|
| 5 KVA | 4 KW | Home backup — essentials |
| 10 KVA | 8 KW | Home backup — full house |
| 20 KVA | 16 KW | Small business / workshop |
| 50 KVA | 40 KW | Commercial building |
| 100 KVA | 80 KW | Industrial / data center |
| 500 KVA | 400 KW | Large facility / hospital |
KVA Calculator FAQ
KVA = kilovolt-amperes, the unit of apparent power. It equals voltage × current ÷ 1000.
KW is real power consumed. KVA is total apparent power. KW = KVA × Power Factor.
KVA = (V × A × 1.732) ÷ 1000. Example: 480V × 100A × 1.732 ÷ 1000 = 83.1 KVA.