How to Calculate Power Factor
What is Power Factor?
Power Factor Calculator helps contractors and tradespeople accurately size, spec, and estimate materials and systems.
Formula
PF = Real Power (kW) / Apparent Power (kVA)
Step-by-Step Guide
- 1Measure real power and apparent power with meter
- 2Apply the formula using your project measurements
- 3Add required safety factors or waste allowances per code
Worked Examples
Input
80 kW real, 100 kVA apparent
Result
PF = 80/100 = 0.80 (80%)
Common Mistakes to Avoid
- ✕Not applying code-required safety factors or derating
- ✕Forgetting to account for waste and cut losses in material estimates
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