Power Factor Calculator — PF and Reactive Power from kW and kVA
CalculatorA power factor calculator divides real power (kW) by apparent power (kVA) to get the power factor and uses √(kVA² − kW²) to find reactive power (kvar).
What is it
Power factor is the ratio of real power to apparent power; the closer to 1, the more efficiently power is used. A low power factor means more current for the same kW load, increasing losses and equipment sizing, and many commercial tariffs charge penalties for it. Real, apparent, and reactive power form a right triangle: kVA² = kW² + kvar².
How to use
- 1Enter real power in kW.
- 2Enter apparent power in kVA.
- 3Press calculate to see the power factor and reactive power.
Reference
| Real power | Apparent power | Power factor | Reactive power |
|---|---|---|---|
| 80kW | 100kVA | 0.8 | 60kvar |
| 90kW | 100kVA | 0.9 | 43.59kvar |
| 95kW | 100kVA | 0.95 | 31.22kvar |
Sources & standards
FAQ
What is the power factor of an 80 kW, 100 kVA load?
PF = 80 / 100 = 0.8, and the reactive power is √(100² − 80²) = 60 kvar.
Why does power factor matter?
A low power factor draws more current for the same real power, increasing wiring losses and transformer sizing, and utilities often bill penalties below a threshold such as 0.9. Capacitor banks are a common correction.
Is power factor input sent to a server?
No. This calculator runs in your browser and does not send input to a server.