kVA to kW Converter
Convert apparent power kVA to real power kW
🔒 No tracking · Method · · Disclaimer · kVA to kW Converter
kVA to kW Converter helps you convert apparent power kVA to real power kW — free, instant, in your browser. Just enter Apparent Power (kVA) and Power Factor; kVA to kW updates the result as you type. kVA to kW puts the headline number first. kVA to kW replaces guesswork. kVA to kW is privacy-first: Engineering inputs stay offline. kVA to kW is part of the Engineering collection on CalcProMaster, alongside kva to kw, free online kva to kw converter and more. Run kVA to kW twice to find the driving input. Open kVA to kW and enter your numbers.
What the defaults give
10 kVA at a power factor of 0.8 is 8.00 kW of real power.
The remaining 6.00 kVAR is reactive power, which does no useful work but still loads the supply.
The formula
kW = kVA × power factor
kVAR = √(kVA² − kW²)
kVA is apparent power, the total the cable and transformer must carry. kW is real power, the part that turns into heat, light or motion. kVAR is the reactive part that charges magnetic fields in motors and transformers and then returns to the source. They form a right triangle, which is why the second formula is Pythagoras rather than a subtraction.
Worked examples
10 kVA at 0.8 → 8 kW, 6 kVAR
10 kVA at 0.6 → 6 kW, 8 kVAR
10 kVA at 0.9 → 9 kW, 4.36 kVAR
10 kVA at 1.0 → 10 kW, 0 kVAR
100 kVA at 0.8 → 80 kW, 60 kVAR
5 kVA at 0.85 → 4.25 kW, 2.63 kVAR
Why the difference decides your bill
Generators, transformers, UPS units and cables are rated in kVA because their limit is current, which depends on total apparent power. A 10 kVA generator at 0.8 can run 8 kW of load; the same generator at 0.6 runs only 6 kW before it reaches its current limit, even though the engine has thermal headroom. Low power factor therefore buys less useful work from the same hardware.
Utilities charge for it too. Industrial tariffs commonly bill reactive power, or apply a penalty below a threshold power factor such as 0.9. Capacitor banks correct the ratio by supplying kVAR locally, raising the power factor toward 1 and freeing capacity without changing the kW the equipment consumes.
Reading the numbers correctly
The power factor is a property of the load, not of the supply. Motors at part load, older fluorescent ballasts, welders and induction furnaces all pull it down; resistive heaters and incandescent lighting sit near 1.0. Modern switch-mode supplies with active correction also run close to 1.0, which is why an office full of IT equipment can have a better power factor than a workshop.
One caution: the calculation assumes a clean sinusoidal supply. With heavy harmonic distortion, the simple kVA × power factor relationship understates the true apparent power, and distortion power factor has to be measured separately. For a quick cable or generator sizing check on ordinary loads, the two formulas above are the right tool.
Frequently Asked Questions
How many kW is 10 kVA?
8 kW at a power factor of 0.8. Multiply kVA by the power factor; at unity power factor the same supply delivers the full 10 kW.
What is the difference between kW and kVA?
kW is real power that does work, kVA is apparent power the supply must carry. The gap is reactive power, measured in kVAR.
Why does power factor matter for a generator?
Generators are limited by current, so a 10 kVA unit at 0.6 can only deliver 6 kW of useful load before hitting that limit, not 10 kW.
How is kVAR calculated?
As the third side of a right triangle: square root of (kVA squared minus kW squared). At 10 kVA and 8 kW that is 6 kVAR.
Can I fix a low power factor?
Yes, with capacitor banks or synchronous correction that supply reactive power locally. That raises the power factor and frees capacity without reducing the kW consumed.
Inductor Energy and other Engineering tools
Inductor Energy · Pump Power Calculator · Wind Load Calculator · Pulley Speed Calculator · Steam Consumption Calculator · Gear Ratio Calculator · Engineering Guides