What is Power Factor ?

Power factor is a measure of how effectively electrical power is being converted into useful work output in an electrical system. It is expressed as a value between 0 and 1 and is often described in terms of lagging (inductive) or leading (capacitive) power factor.

A power factor calculator is very useful tool for several reasons particularly in industrial and commercial electrical systems. There are several reasons why power factor formula and calculations are valuable.
• Energy efficiency : Power factor is a measure of how effectively electrical power is being converted into useful work. A low power factor indicates that a significant portion of the electrical power is being wasted on reactive components such as inductors or capacitors, rather than performing useful work. By calculating and improving the power factor, businesses can reduce energy waste and improve energy efficiency.
• Cost Savings: Many utility companies charge industrial and commercial customers based on their power factor. A poor power factor can result in penalties or higher electricity bills. Using a power factor calculator, businesses can assess their power factor and take measures to improve it, potentially saving money on electricity costs.
• Equipment Efficiency: Electrical equipment such as motors, transformers, and lighting systems may operate more efficiently at a higher power factor. Calculating the power factor can help determine if equipment is operating optimally or if improvements are needed for better performance and longer lifespan.
• Power factor calculations are essential for capacity planning in electrical systems.
• By assessing and improving the power factor, businesses can maintain stable voltage levels and prevent voltage related issues.

The power factor formulas for both single phase and three phase electrical systems are based on ratio of real power (in watts) to apparent power (in volt-amperes).

Power Factor Formula single phase

Following is the single phase power factor formula. As mentioned it is the ratio of real power to apparent power.

power factor formula for single phase

Here Real power (W) is the actual power consumed in watts. Apparent power is the product of voltage (V) and current (I) in volt-amperes.

Power Factor Formula 3 phase

Following is the 3 phase power factor formula used in this calculator. As mentioned it is the ratio of real power to (V*I).

power factor formula for three phase

In three-phase systems, the factor of √3 is included in the denominator because the power calculation takes into account the root-mean-square (RMS) values of voltage and current for each phase, and there is a 120-degree phase difference between the phases in a balanced system. The √3 factor ensures that the power formula accounts for this phase difference.

Power Factor Calculator for Single Phase

Power in KW (input1) :

Voltage in Volts (input2) :

Current in Amps (input3) :


Single Phase Power Factor (output) :

EXAMPLE #1 Power factor calculation for single phase:
INPUTS: Power(KW) = 10KW , Voltage = 120Volts, Current = 80Amp
OUTPUT: Single Phase Power Factor = 1.041

Power Factor Calculator for Three Phase

Power in KW (input1) :

Line Voltage in Volts (input2) :

Current in Amps (input3) :


Three Phase Power Factor (output) :

EXAMPLE #2 Power factor calculation for three phase :
INPUTS: Power(KW) = 10, V(L-L) = 120Volts, I = 80Amp
OUTPUT: Three Phase Power Factor = 0.602

Conclusion : Power factor calculator and its formulas are very useful in electrical systems, whether they are single phase or 3 phase. They help to determine how effectively electrical power is being used in a given system.


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