About the kW to kVA Calculator
This calculator converts kW to kVA. kW is a thousand watts, the usual way to rate motors, heaters, air conditioners and generators, and kVA is a thousand volt-amperes, the apparent power rating of transformers, generators and UPS units. It divides the real power by the power factor and shows the reactive power too. Enter your figures and the answer appears at once, together with a few related values, and you can copy the result with one tap. The sums are done in your browser and nothing is sent anywhere.
Updated October 2026
How to use the kW to kVA Calculator
- 1Enter the value in kW.
- 2Fill in the other boxes that the kW to kVA calculation needs, such as time, voltage or power factor.
- 3Read the answer in the large result box.
- 4Check the extra rows for related values.
- 5Press Copy result to keep it.
When you need kW to kVA
When you add up the loads you want to run, you get kilowatts. Generators, transformers and UPS units are sold in kVA. To choose the right size you divide the kilowatts by the power factor. A lower power factor means a bigger kVA rating for the same real power.
Installers use the sum to size a standby generator, and utilities use it to size a transformer. If the load is motors, the power factor is lower and the kVA need is higher. Improving the power factor, for example with capacitors, reduces the kVA that the supply must carry.
How the kW to kVA sum works
kVA = kW ÷ power factor. A workshop with machines using 8 kW at a power factor of 0.8 needs 8 ÷ 0.8 = 10 kVA of supply.
The displayed answer is rounded to six significant figures, but the sum itself is not rounded, so converting kW to kVA and back again gives you the number you started with.
- Add a margin for starting currents
- Lower PF needs a larger kVA
- Check the rating plate
Mistakes to avoid when converting kW to kVA
A mistake is to buy a generator by its kW only, or to treat 1 kW as 1 kVA. Add a margin for starting currents too, because a motor can draw several times its running current for a moment when it starts.
On phone and computer
On a phone, type in the boxes one after another and read the kVA result underneath; the Copy button puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the kVA value move. The kW to kVA page works the same on both. Use kVA to kW Calculator to check the answer by going back, and Power Factor Calculator to find the factor if you do not know it. kW to Amps Calculator turns the load into a current for cable and breaker choices.
Features
- kW to kVA in one step
- Related values shown with the answer
- Clear messages for impossible inputs
- Copy the result with one tap
- Private: nothing is uploaded
- Works on phone and computer
Frequently asked questions
How do I convert kW to kVA?
kVA = kW ÷ power factor. A workshop with machines using 8 kW at a power factor of 0.8 needs 8 ÷ 0.8 = 10 kVA of supply.
What is the formula for kW to kVA?
kVA = kW ÷ power factor. The calculator applies it exactly and rounds only the displayed answer.
What is the difference between kW and kVA?
kW is a thousand watts, the usual way to rate motors, heaters, air conditioners and generators. kVA is a thousand volt-amperes, the apparent power rating of transformers, generators and UPS units. They measure different things, which is why converting from kW to kVA needs more than a simple multiplication in some cases.
How many kVA do I need for 10 kW?
At a power factor of 0.8 you need 12.5 kVA; at 1.0 you need 10 kVA; at 0.9 about 11.1 kVA.
Why is kVA larger than kW?
Because kVA includes reactive power that does no work but still flows through the wires. The power factor describes how much of the apparent power is real.
Is this kW to kVA calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so the figures you type are not uploaded or stored. It is meant for planning and learning; for wiring or safety work, check the result against your equipment's rating plate and local rules.