Watts to kVA Calculator
Convert Watts to kVA with the formula, a worked example and a table of typical values. Working shown step by step.
Try your own numbers
Estimate only. Not engineering or safety advice. Check the result against the applicable standard and the equipment data, and have a competent engineer review it before it is relied on. Terms of use.
Open in the calculator with these values
Formula
Worked example
| Input | Value |
|---|---|
| Real power | 80,000 W |
| Power factor | 0.8 |
- S = P / pf = 80 kW / 0.8 = 100 kVA
- Q = √(S² − P²) = 60 kVAR
Typical values
| Real power (W) | Apparent power (kVA) |
|---|---|
| 1,000 | 1.25 |
| 5,000 | 6.25 |
| 10,000 | 12.5 |
| 50,000 | 62.5 |
| 80,000 | 100 |
| 100,000 | 125 |
Other inputs are the same as in the worked example above.
Assumptions
- Sinusoidal waveforms
- Lagging or leading is not distinguished (Q is magnitude)
Use the power factor correction calculator to size capacitors.
Frequently asked questions
How do I convert Watts to kVA?
S = P / pf; Q = √(S² − P²). Worked example: Real power 80,000 W, power factor 0.8 gives 100 kVA.
What do I need to enter?
Enter real power and power factor. Change the unit of a value with its selector and the result stays the same.
Which power factor should I use?
Read it from the equipment nameplate or data sheet. Typical values are only a guide: about 1.0 for a resistive load and about 0.85 for a fully loaded induction motor. Do not use typical values for accurate work.
Is kVA the same as kW?
No. kVA (or VA) is apparent power and kW (or W) is real power. Real power = apparent power × power factor, so the two are equal only when the power factor is 1.
How accurate are the results?
Every figure comes from the same tested engine as the Elecmetric calculators and is meant for estimating. Check design values against the standard and the equipment data you work to.
Related
Next steps in a design: Power Factor CorrectionkW to Amps
Opposite direction: kVA to Watts
Also see: kVA to kW kW to kVA kVA to VA VA to kVA
Formula guides: Power Factor and the Power TriangleThree-Phase Power Formulas
All 78 conversionskW to kVA and kVAR in Elecmetric