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kVA to kW Calculator
Convert kVA to kW and kW to kVA using the power factor, with reactive power (kVAR) and the current in amps for single-phase or three-phase supplies.
How to use it
- Choose whether you know the apparent power (kVA, as on generator and transformer plates) or the real power (kW).
- Enter the power factor - 0.8 is the common rating for generators; resistive loads such as heaters are 1.0.
- Pick single or three phase and enter the voltage (line-to-line for three phase) to get the current.
How it works
Real power kW = kVA × power factor. Apparent power kVA = kW ÷ power factor. Reactive power kVAR = kVA × sin(arccos(pf)). Current = kVA × 1,000 ÷ voltage for single phase, or kVA × 1,000 ÷ (√3 × voltage) for three phase.
Equipment is rated in kVA because the wiring and windings must carry the full current, whether or not it does useful work. A 50 kVA generator at 0.8 power factor delivers 40 kW; a poor power factor wastes capacity and may attract utility penalties for commercial users.
FAQ
How do I convert kVA to kW?
Multiply kVA by the power factor: 100 kVA × 0.8 = 80 kW. With a power factor of 1 (resistive load) kVA and kW are equal.
What power factor should I assume?
Use 0.8 for generators and general mixed loads, 0.9-0.95 for modern motors and corrected installations, 1.0 for heaters and incandescent loads.
How many amps is 100 kVA?
On a 400 V three-phase supply, 100 kVA is about 144 A; on 240 V single phase it is about 417 A.
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