What is the difference between a Watt and Horsepower (hp)?

Both are units of power. The Watt is the standard SI unit for power (electrical and mechanical), while horsepower is an older unit still commonly used for rating engines and motors. 1 mechanical horsepower is equal to approximately 745.7 watts.

Why do I need to convert between these power units?

Converting between units is common in engineering. You might need to compare the electrical power consumption (in kW) of a motor with its mechanical output rating (in hp), or scale measurements from small circuits (var) to large grids (Mvar).

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Q: What is reactive power (var, kvar)?

Reactive power is the power that flows back and forth in an AC circuit, which means it moves in both directions in the circuit or is stored and discharged. It is measured in Volt-Amperes Reactive (var) and is essential for creating the magnetic fields required by motors and transformers to operate.

Q: What is real power (W, kW)?

Real power, also known as active power, is the power that actually performs work in a circuit, such as creating heat, light, or motion. It is measured in Watts (W). Our Power Converter tool handles these units.

A suite of free, fast tools for your electrical calculations. Instantly convert between units of reactive power (var, kvar) and real power (watts, hp).

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Reactive Power (var) Real Power (W)

Reactive Power Unit Converter

Enter a value, select the units (var, kvar, Mvar), and get the result instantly.

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Real Power Converter

Instantly convert between watts, kilowatts, megawatts, and horsepower.

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A Guide to Understanding Electrical Power

Explore the concepts of real, apparent, and reactive power, and understand why managing them is crucial in AC systems.

The Power Triangle: More Than Just Watts

In DC circuits, power is simple. In AC circuits, however, the relationship between voltage and current gives rise to three types of power, often visualized as the "Power Triangle":

Real Power (P): Also called Active Power, this is the "working" power that lights bulbs and turns motors. It is measured in Watts (W). Our Real Power Converter handles these units.
Reactive Power (Q): This is the power required to create magnetic fields in motors and transformers. It doesn't perform work but is essential. It is measured in Volt-Amperes Reactive (var). Our Reactive Power Converter handles these units.
Apparent Power (S): This is the vector sum of Real and Reactive Power, representing the total power the grid must supply. It is measured in Volt-Amperes (VA).

Why Convert Power Units?

Converting between different units of power is a daily task in many fields of engineering and science. Our tools are designed to make this seamless:

Scaling (W, kW, MW): Just like distance can be measured in meters or kilometers, power is scaled for convenience. A light bulb might use 60W, while a power plant generates 500MW.
Electrical vs. Mechanical (W vs. hp): It is often necessary to relate the electrical power consumed by a motor (in kW) to its mechanical power output (in hp). Our Real Power converter makes this comparison simple.
Reactive Power Scaling (var, kvar, Mvar): Similar to real power, reactive power is scaled for different applications, from small components (var) to industrial capacitor banks (kvar) and entire power grids (Mvar).

How Our Converters Help

Our suite of tools empowers you to handle these conversions effortlessly. Both tools operate entirely in your browser, ensuring your data is private and calculations are instantaneous. They are reliable companions for professionals, students, and enthusiasts working with AC power systems.

Frequently Asked Questions

Find answers to common questions about our Power Converter tools.

What is reactive power (var, kvar)?

Reactive power is required to create magnetic fields in AC equipment like motors. It doesn't do physical work but is essential for the system to operate. It is measured in Volt-Amperes Reactive (var).

What is real power (W, kW)?

Real power is the power that performs actual work, like creating heat, light, or mechanical motion. It is measured in Watts (W).

What's the difference between Watts and Horsepower?

Both are units of power. The Watt (W) is the standard international unit. Horsepower (hp) is an older unit still widely used for motors and engines. 1 mechanical horsepower equals about 745.7 watts.

Are these converters free to use?

Yes, both our Reactive Power Converter and Real Power Converter are completely free for everyone to use, without any limits or sign-ups.

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