Power factor is the missing variable between kVA nameplates and kW loads. This guide shows how to convert kVA to kW using power factor—apparent rating, PF as a decimal (0–1), and real power for sizing and billing checks.
Benefits
- Formula: kW = kVA × power factor (PF).
- PF from utility meter, motor nameplate, or conservative load assumptions.
- Reverse: PF = kW ÷ kVA to audit measured site power factor.
How it works
- Read kVA from equipment nameplate or one-line diagram.
- Enter power factor—measured, catalog, or typical (e.g. 0.85 for motor mix).
- Multiply for kW; compare to sum of connected real loads.
FAQ
How do I convert kVA to kW using power factor?
kW = kVA × PF. Example: 25 kVA UPS at 0.9 PF → 25 × 0.9 = 22.5 kW deliverable real power. Enter PF as decimal: 90% = 0.9, not 90.
Where do I get power factor for the calculation?
Best: read PF from a power quality meter on the load bus. Next: motor and lighting schedules—resistive ~1.0, motors ~0.75–0.9. When unsure, use a conservative PF (lower) so kW estimate is not optimistic.
Can power factor be greater than 1?
For this converter, enter PF between 0 and 1 for lagging/unity AC loads. Leading PF or capacitive correction can exceed 1 in theory but is uncommon in simple sizing. Values above 1 in the tool are rejected—stick to decimal PF from your meter or spec.
Technical specifications
- kW = kVA × PF.
- PF = cos(φ) for linear AC loads.
- Measured PF = kW ÷ kVA (from meter registers).
- Related: kva-to-kw-converter, inverter-sizing, amps-to-watts.