Power Factor Calculator | PES Supply
Power Factor Calculator
Calculate power factor, apparent power, and reactive power for AC circuits
Power Factor Reference
| Device Type | Typical PF | Notes |
|---|---|---|
| Resistive (heater, incandescent) | 1.0 | Perfect PF |
| LED lights (with driver) | 0.9-0.95 | Good |
| Computer/IT equipment | 0.95-0.99 | PFC corrected |
| Older fluorescent lights | 0.5-0.7 | Needs correction |
| AC motors (unloaded) | 0.3-0.5 | Poor PF |
| AC motors (loaded) | 0.8-0.9 | Good |
| Welding equipment | 0.5-0.7 | Reactive load |
What is Power Factor?
Power factor (PF) is the ratio of real power (watts) to apparent power (volt-amperes). It measures how efficiently electrical power is used:
- PF = 1.0 — All power is used efficiently (resistive load)
- PF = 0.8 — 80% of power does useful work, 20% is wasted as reactive power
- PF < 0.9 — Utility may charge penalty for commercial customers
Formula: PF = Real Power (W) / Apparent Power (VA) = cos(φ)
Reactive Power: Q = √(VA² - W²) in VAR (volt-ampere reactive)