What Is the kVA to kW Calculator?
This calculator converts apparent power, measured in kilovolt-amperes (kVA), into real (active) power, measured in kilowatts (kW). The conversion depends on the power factor (PF) of the electrical system, which describes how efficiently current is being converted into useful work. This tool is universal and applies to any AC electrical system worldwide.
How to Use It
Enter the apparent power in kVA and the power factor (a value between 0 and 1). The calculator instantly returns the real power in kW, plus the reactive power in kVAR. A purely resistive load has a power factor of 1, while inductive loads such as motors typically range from 0.7 to 0.9.
The Formula Explained
The core relationship is $$\text{kW} = \text{kVA} \times \text{PF}$$ Apparent power (kVA) is the total power flowing in the circuit, real power (kW) is the portion that does useful work, and the power factor is the ratio between them. The reactive power, which sustains magnetic fields in motors and transformers, follows \(\text{kVAR} = \text{kVA} \times \sqrt{1 - \text{PF}^2}\), forming the classic power triangle.
Worked Example
Suppose a generator is rated at 100 kVA and the load has a power factor of 0.8. The real power is $$100 \times 0.8 = 80 \text{ kW}$$ The reactive power is $$100 \times \sqrt{1 - 0.64} = 100 \times 0.6 = 60 \text{ kVAR}$$ So this generator can deliver 80 kW of usable power under these conditions.
FAQ
Why is kW always less than or equal to kVA? Because the power factor is at most 1. The kW value only equals kVA when the power factor is exactly 1 (a perfectly resistive load).
What power factor should I use? Use the rated power factor of your equipment. If unknown, 0.8 is a common assumption for mixed industrial and commercial loads.
Does this work for single- and three-phase? Yes. The kVA-to-kW relationship via power factor holds regardless of the number of phases.
