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kVA to kW / kW to kVA Converter

Convert between apparent power (kVA) and real power (kW)

Reference Info & Formulas
Power Triangle

kW = kVA × PF

kVA = kW / PF

kVAR = √(kVA² - kW²)

kVA — Apparent power

kW — Real (useful) power

kVAR — Reactive power

Typical PF Values

1.0: Heaters, kettles

0.95: Corrected supply

0.85: Typical motor

0.7: Poor — needs correction

Input
Enter power value and power factor
kVA

Data: Standard electrical formulas (kW = kVA × PF)

For guidance only. The responsibility for any electrical installation lies with the qualified person carrying out the work. Always verify calculations independently and apply professional judgement.

How This Calculator Works

kVA, kW, and kVAR form the power triangle — understanding their relationship is essential for sizing generators, UPS systems, and commercial supplies.

kVA is apparent power (the total power flowing in the circuit), kW is real power (the power doing useful work), and kVAR is reactive power (the power sustaining magnetic and electric fields). The power factor is the ratio of real to apparent power and determines how efficiently the supply is being used.

kW = kVA × Power Factor
kVA
= Apparent power
PF
= Power factor (0–1)
kW
= Real (active) power

The three quantities are related by the power triangle. If you know any two values, you can calculate the third using the Pythagorean relationship below.

kVA² = kW² + kVAR²
kVA
= Apparent power (hypotenuse)
kW
= Real power (adjacent side)
kVAR
= Reactive power (opposite side)

Quick Reference — Power Factor Effect

Real power output at different power factors (10kVA supply)

Apparent PowerPower FactorReal Power (kW)Reactive Power (kVAR)
10 kVA1.0010.00.0
10 kVA0.959.53.1
10 kVA0.858.55.3
10 kVA0.808.06.0
10 kVA0.707.07.1

kVAR calculated as √(kVA² − kW²). Lower power factor means more reactive current for the same useful output.

Practical Notes

Generator and UPS Sizing

Generators and UPS systems are rated in kVA, not kW. A 10kVA generator at 0.8 power factor delivers only 8kW of usable power. Always check the manufacturer's stated power factor when sizing standby supplies for the actual kW load.

Current Penalty of Poor Power Factor

Poor power factor increases current for the same real power output. At PF 0.7, you draw 43% more current than at PF 1.0 for identical kW. This directly affects cable sizing, switchgear ratings, and transformer capacity.

DNO Reactive Power Charges

Distribution Network Operators may impose reactive power surcharges on commercial installations with a power factor below 0.95. Power factor correction capacitors can bring PF back above 0.95 and avoid these penalties.

Frequently Asked Questions

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