Power Factor Calculator: AC Circuits and Electri...
Calculate power factor, reactive power, and apparent power for AC circuits. Understand why power factor correction reduces energy waste in industrial systems.
What is Power Factor?
Power factor (PF) is the ratio of real power (doing useful work) to apparent power (total power supplied by the source) in an AC circuit. A PF of 1.0 (unity) means all supplied power does useful work. Inductive loads (motors, transformers) cause PF < 1, wasting energy and requiring larger electrical infrastructure.
⚡ Power Factor Calculator
Free calculator for instant results.
📐 Formula
PF = cos(φ) = P / S
P = real power (W), S = apparent power (VA), φ = phase angle between voltage and current. Reactive power Q (VAR): S² = P² + Q².
📝 Worked Example
Motor: P=1000W (real), S=1250 VA (apparent):
PF = 1000/1250 = 0.8 (lagging)
Q = √(1250²−1000²) = 750 VAR (reactive power wasted)
📝 How to Use
❓ FAQ
Why does low power factor cost money?
Utilities supply larger apparent power but bill only for real power. Low PF requires larger cables, transformers, and generators for the same useful output.
How is power factor corrected?
By adding capacitor banks in parallel with inductive loads. Capacitors supply reactive power locally, reducing reactive draw from the grid and improving PF.
Veer Kumavat
Founder & AuthorVeer is a 14-year-old student from Nashik, Maharashtra, who built SciFi Calculators to help students worldwide master STEM subjects. He is passionate about making complex science and math problems accessible through intuitive digital tools.