What this converter does
This converter switches between apparent power (kVA, what the supply must deliver) and real power (kW, the work actually done) using the power factor. Enter your kVA and PF to find the real load — or swap the arrow to go from kW back to kVA. The result updates as you type.
Power factor is the ratio of real to apparent power. A typical motor runs near 0.8; a resistive heater is 1.0. The higher the PF, the more of your kVA turns into useful kW. To size a supply from a kW figure, use the kW to kVA converter.
The units it covers
These are the three faces of AC power plus the ratio that links them — kVA is the vector sum of kW and kVAR.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Apparent power | kVA | S | Sizing generators, transformers, cables |
| Real power | kW | P | Useful work; the energy you are billed for |
| Reactive power | kVAR | Q | Magnetising motors and transformers |
| Power factor | PF | P÷S | Ratio 0–1; how much apparent power does work |
The formula
Real power is apparent power multiplied by the power factor:
kW = kVA × PF (and kVA = kW ÷ PF)Where:
- kVA = apparent power — what the supply must carry
- kW = real power — the useful work delivered
- PF = power factor, between 0 and 1
Worked example
A 25 kVA generator supplies a load at power factor 0.8. Find the real power.
kW = kVA × PF25 × 0.8 = 20 kWA 25 kVA generator delivers 20 kW of real work at 0.8 PF.
The units in this example
The total power the supply must deliver — the vector sum of real and reactive power. Generators, transformers and cables are sized in kVA.
- kVA = kW ÷ PF
- 1 kVA = 0.8 kW at 0.8 PF
- 1 kVA = 1 kW at unity PF
- 1 MVA = 1,000 kVA
The power that does useful work — turning a motor, producing heat or light. It is what an energy meter bills and equals kVA × power factor.
- kW = kVA × PF
- 1 kW = 1.25 kVA at 0.8 PF
- 1 kW = 1 kVA at unity PF
- 1 kW = 1,000 watts