Real and Reactive Power Calculator

Real and Reactive Power

In an AC circuit, real power, expressed in watts (W), is the actual electrical energy transferred from a power source to a load. It is in charge of carrying out beneficial tasks like running motors and illuminating bulbs.
The amount of power that oscillates between the source and the load without producing useful work is known as reactive power, and it is measured in volt-amperes reactive (VAR). Rather, it generates and maintains electric and magnetic fields in the circuit’s inductive and capacitive components.

Real power is primarily used to supply energy for electrical systems’ beneficial tasks, enabling the operation of machinery and devices.
In order for inductive and capacitive components in AC circuits to function, the electromagnetic fields that are required for their establishment and maintenance require reactive power.

Understanding Real and Reactive Power:

Real Power (P):

Real power, alternatively referred to as active power, denotes the genuine power utilized by a load within an electrical circuit. Quantified in watts (W), it symbolizes the energy transmitted from the source to the load. Real power is accountable for executing tasks, such as illuminating a light bulb or propelling a motor.

Reactive Power (Q):

Reactive power, alternatively termed as reactive voltage or current, denotes the energy stored within the magnetic and electric fields of either an inductor or capacitor within an electrical system. Quantified in vars (VAR), it accounts for the phase displacement observed between voltage and current in an AC setup. Despite not contributing to productive work, reactive power may induce energy dissipation within the system.

Importance of Real and Reactive Power:

Comprehending real and reactive power holds significant importance within the realm of electrical engineering. It enables engineers and operators to:

  • Develop energy-efficient electrical systems, reducing energy wastage and enhancing power transmission.
  • Fine-tune the functionality of motors, generators, and related machinery for optimal performance.
  • Detect and rectify power factor issues that may lead to energy loss and operational inefficiencies.
  • Guarantee the secure and dependable operation of electrical infrastructures.


  • Power Distribution
  • Power Factor Correction
  • Electric Grid Stability
  • Power Quality Improvement
  • Industrial Applications


In essence, genuine power denotes the active energy utilized by a load, whereas reactive power signifies the energy stored within magnetic and electric fields. Apparent power combines both real and reactive power vectors, while power factor denotes the proportion of real power to apparent power. Comprehending these principles is pivotal for the effective design and operation of electrical systems, ensuring efficiency and reliability.

Reactive and actual power can be computed online with our calculator. Using the supplied voltage and current data, calculate the active power (also known as real power) and reactive power (also known as volt-ampere reactive, or VAR). Both single-phase and three-phase power systems can use this calculator.

Note : Don’t end with comma ( , )

Phase Type
Voltage (v)
Current (i)
Phase Angle (p)


For Single Phase

\[t = v * i * cos(p) \\r = v * i * sin(p)\]

For Three Phase

\[t = \sqrt{3} * v * i * cos(p) \\r = \sqrt{3}*v * i * sin(p)\]


  • t = Real power
  • r = Reactive power
  • v = Voltage
  • i = Current
  • p = Phase Angle

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