kVA to kW Converter
| Generator | kVA | kW at 0.8 PF | Typical role |
|---|---|---|---|
| 1 kVA | 0.8 | camping inverter | |
| 3 kVA | 2.4 | small home standby | |
| 5 kVA | 4 | site / rental counter | |
| 7.5 kVA | 6 | large home standby | |
| 10 kVA | 8 | small shop | |
| 20 kVA | 16 | restaurant / workshop | |
| 100 kVA | 80 | building supply |
kW = kVA x power factor - and for generators, the industry writes that factor down: 0.8. So the 5 kVA site generator every rental counter stocks delivers 4 kW of real work, a 7.5 kVA home standby carries 6 kW, and a 100 kVA building unit shoulders 80 kW of load. Type either figure and the converter fills in the other live, with the power factor as an honest third field you can actually change.
Why the two numbers exist: kVA measures what the alternator must carry - volts times amps, regardless of what the load does with them - while kW measures the work you actually get. The gap is power factor, and it is real money: motors, compressors and fridges draw current that makes no watts, so a generator sized in kW alone runs out of amps long before it runs out of work. The table below lines up the common generator sizes at the standard 0.8, so the rental counter conversation starts settled.
How to use
- Type the kVA from the generator's data plate, or the kW of your load, and the other appears instantly.
- Leave power factor at 0.8 for generator sizing - that is the rating basis the plate itself assumes.
- Load the generator to 80% at most for continuous running; the conversion above is capacity, not a usage target.
Frequently asked questions
Why are generators rated in kVA instead of kW?
Because the alternator does not know what you plug in. Its windings heat according to current - volts times amps - whether that current turns into watts or merely sloshes in and out of a motor's magnetic field. A diesel generator feeding 0.8-PF load makes the alternator carry the same amps as a resistive load drawing a fifth more kW, so the honest rating is the one that measures amps carried: kVA. kW ratings would flatter the machine whenever power factor dips.
How many kW is 5 kVA?
4 kW at the standard 0.8 power factor: 5 x 0.8. The same 5 kVA would deliver 4.5 kW to 0.9-PF load or the full 5 kW to pure resistive heaters - the machine never changes, the load's appetite for idle current does. That is why generator makers print both, and why sizing math always starts from the smaller kW number.
What is power factor in plain words?
The beer analogy survives because it is true: kW is the beer you drink, kilovars are the foam you cannot, and kVA is the whole mug the bartender poured. Power factor is the beer-to-mug ratio - how much of the current you pay to carry actually does work. Resistive heaters pour a full mug (PF 1.0); induction motors pour one with a thick head (0.8-0.9); the generator must carry the entire mug either way.
What power factor should I use for sizing?
0.8 is the safe default because it matches the generator rating convention and typical mixed motor loads. Resistive-only loads (heaters, kettles, incandescent) run at 1.0; individual motors read 0.8-0.85 off their plates; modern electronics with power-factor correction sit near 0.95+. When in doubt, size at 0.8 - oversizing costs fuel, undersizing trips the breaker.
Can power factor be higher than 1?
No - it is a ratio of real power to apparent power, and real power can never exceed what the current carries. It can, however, be improved toward 1: capacitor banks cancel a motor's magnetic sloshing, which is why factories with big motor fleets install correction gear - utilities charge for the foam. A corrected 0.75 site crawling to 0.95 frees real capacity without buying a bigger generator.