Power Factor Calculator

Use our Power Factor Calculator to quickly determine all key AC power parameters, including true power (P), reactive power (Q), apparent power (S), power factor (PF), andphase angle (φ). Enter any three known values and the tool will instantly compute the missing ones using the fundamental AC power equations: S² = P² + Q², PF = P / S, and PF = cos φ. This calculator is ideal for electrical engineering,industrial power systems, motor loads,transformers, and energy efficiency optimization.

What Is Power Factor?

Power factor is a key measure of how efficiently electrical power is converted into useful work. It represents the ratio between true power (P) and apparent power (S):

PF = P / S

A power factor of 1 means all supplied power is used effectively, while alow power factor indicates wasted energy due to reactive loads such as motors, inductors, or transformers. Improving power factor reducessystem losses, electricity bills, and boostsoverall system efficiency.

True Power, Reactive Power, and Apparent Power

In AC circuits, electrical power is divided into three components:

• True Power (P) — measured in watts (W), it represents the real work performed. • Reactive Power (Q) — measured in VAR, it represents energy exchanged between source and reactive components. • Apparent Power (S) — measured in VA, it is the vector sum of P and Q.

Their relationship forms the well-known power triangle:

S² = P² + Q²

This equation allows the calculator to compute any unknown value automatically. Understanding these quantities is essential for AC design,motor control, UPS systems,grid installations, and power-quality diagnostics.

Power Factor and Phase Angle

The phase angle φ between voltage and current determines how much power is actually used. It is directly linked to the power factor through the cosine function:

PF = cos φ

A larger angle means more reactive behavior, reducing power factor. By computing φ, P, Q, S, and PF, this calculator gives you full insight into your AC system’s performance. It is ideal for industrial audits, energy saving,motor sizing, transformer loading, andelectrical safety analysis.