Generators
Generator kVA vs kW: What's the Difference?
kVA (kilovolt-amperes) is the generator's apparent power rating; kW (kilowatts) is the real, usable power output. For most diesel generators at a 0.8 power factor, kW is roughly 80% of the kVA figure, so a 500 kVA generator delivers approximately 400 kW.
| Formula | kW = kVA × power factor (typically 0.8) |
|---|---|
| 500 kVA ≈ | 400 kW |
| 1000 kVA ≈ | 800 kW |
Why generators are rated in kVA
kVA reflects the total apparent power the alternator can supply, including both the real power (kW) that does useful work and the reactive power drawn by inductive loads like motors and compressors.
Manufacturers rate generators in kVA because it reflects the electrical capacity of the machine regardless of what power factor the connected load ends up having.
Converting between the two
To estimate real power from a kVA rating, multiply by the assumed power factor: commonly 0.8 for standard diesel generators. To go the other way, divide your required kW by 0.8 to find the minimum kVA rating needed.
Common mistakes
- Assuming kVA and kW are interchangeable when sizing a generator.
- Using a 1.0 power factor assumption, which overstates available real power.
Related questions
0.8 is the standard assumption unless the supplier states otherwise: confirm for precise industrial load calculations.
Reviewed 2026-09-01. Technical references: manufacturer documentation and internal fleet data.