Convert a volt-ampere rating into the kilowatts of real power it delivers at your load power factor.
Starting from an apparent-power rating instead? Use the main kVA to kW converter for any power factor.
Every diagram and table on this page updates with the calculator above.
Without the power factor you only know the current the supply must carry, not the work done.
A 1,500 VA supply at 0.9 power factor delivers 1.35 kW. The missing 150 VA is not lost as heat — it flows back and forth between source and load every cycle, doing nothing but occupying the cable.
Power factor is the cosine of the angle between the voltage and current waves. When current lags voltage, part of every cycle pushes energy back towards the source instead of into the load.
Switch-mode supplies without correction draw current in sharp spikes rather than a lagging sine wave. The result is a poor true power factor even though the displacement angle looks fine.
The reason a modern power supply has a power factor at all is its input stage. A bare rectifier and capacitor draws current only at the peaks of the voltage wave, producing a spiky, harmonic-rich current.
The incoming AC is converted to DC, charging a bulk capacitor near the peak of each half-cycle.
Active PFC shapes the input current back into a sine wave in phase with voltage, lifting true power factor above 0.95.
A high-frequency converter produces the output rails your equipment actually uses.
This is why two 500 W devices can present very different loads to a UPS: the one with active PFC draws around 520 VA, while an uncorrected unit can demand 800 VA or more.
Everyday VA ratings converted at your selected power factor.
| VA | Real power (kW) | Real power (W) |
|---|---|---|
| 100 VA | 0.09 | 90 |
| 250 VA | 0.225 | 225 |
| 500 VA | 0.45 | 450 |
| 650 VA | 0.585 | 585 |
| 750 VA | 0.675 | 675 |
| 1,000 VA | 0.9 | 900 |
| 1,500 VA | 1.35 | 1,350 |
| 2,000 VA | 1.8 | 1,800 |
| 3,000 VA | 2.7 | 2,700 |
| 5,000 VA | 4.5 | 4,500 |
| 7,500 VA | 6.75 | 6,750 |
| 10,000 VA | 9 | 9,000 |
| 15,000 VA | 13.5 | 13,500 |
| 20,000 VA | 18 | 18,000 |
| Marking | What it means | Use it for |
|---|---|---|
| Input: 100–240 V ~ 1.5 A | Worst-case input current at the lowest voltage | Circuit and fuse sizing |
| Input: 150 VA | Apparent power drawn from the supply | UPS and cable capacity |
| Output: 19 V ⎓ 4.7 A | DC output, about 89 W | What the device actually receives |
| Efficiency: 88% | Output ÷ input real power | Estimating heat and running cost |
The adapter draws about 108 VA and delivers 90 W, wasting roughly 12 W as heat.
Converting VA to kW is usually a step in a bigger job: working out what a floor actually draws so you can size a supply, a UPS or a standby generator without guessing.
Record the input VA or the input voltage and current from each nameplate.
Plug-in meters cost little and typically reveal 30–50% less real consumption than nameplates claim.
Nothing runs flat out simultaneously. A diversity factor of 0.6–0.8 is realistic for office equipment.
Turn each VA figure into kW at its own power factor, then add the kilowatts.
29 calculators built on the same maths as the tool above. Each one has its own inputs, interactive diagrams and worked examples.
Common questions about converting va to kw.