kVA to kW Calculator
kVA to kW Calculator
Understanding kVA vs kW is essential when sizing generators, UPS systems, and transformers. The difference comes down to power factor - how efficiently electrical power is being converted to useful work.
Conversion Formula
kW = kVA × PF (real power). kVAR = kVA × √(1 - PF²) (reactive power). Together: kVA² = kW² + kVAR² (the power triangle).
Step-by-Step Examples
10 kVA, PF=0.8 = 8 kW, 6 kVAR
10 × 0.8 = 8 kW; 10 × √(1-0.64) = 6 kVAR
20 kVA, PF=1.0 = 20 kW, 0 kVAR
PF=1 means purely resistive load - all power is real
Frequently Asked Questions
What is the difference between kVA and kW?
kVA (kilovolt-amperes) is apparent power - the total power drawn by a circuit including both useful and reactive components. kW (kilowatts) is real power - the actual work-producing power. The ratio kW/kVA is the power factor.
Why are generators rated in kVA instead of kW?
Generators are rated in kVA because the generator itself does not know what power factor the load will have. The kVA rating represents the maximum current and voltage the generator can supply, regardless of load type.
What is reactive power (kVAR)?
Reactive power (kVAR) is the portion of apparent power that does no useful work but is needed to maintain magnetic and electric fields in inductive and capacitive loads like motors and transformers. It causes current to flow without performing real work.