kW to kVA calculator
Convert kilowatts (real power) to kilovolt-amperes (apparent power), or the other way round, using the power factor cos φ. You also see the reactive power.
In kW or in kVA, depending on your choice.
Between 0 and 1. For generators and UPS systems 0.8 is common.
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How it's worked out
How it works
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Enter the values
Type the numbers or the formula. Decimals may use a point or a comma. No idea? Click Fill in an example.
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Instant answer
The answer appears as you type, with the most important intermediate values.
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See the working
Under "How it's worked out" you see the steps, handy for checking your own calculation.
The difference between kW and kVA
- kW is real power: what an appliance actually turns into heat, light or movement.
- kVA is apparent power: voltage × current, which is what the supply and a generator have to provide.
- They are linked by the power factor: kW = kVA × cos φ.
A 100 kVA generator with a power factor of 0.8 can therefore deliver 80 kW of real power. The other way round, an 80 kW load at 0.8 needs a generator of at least 80 ÷ 0.8 = 100 kVA.
Reactive power
The difference between the two is the reactive power in kvar: √(kVA² − kW²). It swings back and forth between source and load without doing useful work, but it still loads cables and the generator. For 80 kW at 0.8 it is 60 kvar.
Which power factor?
For generators and UPS systems 0.8 is common; modern UPS units are often rated at 0.9 or 1. Electric motors are usually between 0.8 and 0.9, and heaters and incandescent bulbs are at 1. Check the rating plate for the exact figure.
To go from power to current, use watts to amps.
Frequently asked questions
Is the kW to kVA free?
Yes. The kW to kVA is completely free, with no account, sign-up or usage limit.
How accurate is the result?
The tool calculates with your browser's number precision. For important calculations, always double-check what you entered.
Does it work on my phone?
Yes. The tool works in any modern browser on a phone, tablet or computer.