Horsepower to Amps Unit Calculator

In electrical engineering and physics, the conversion of electric motor horsepower (Hp) to amps is a frequently encountered process. Horsepower is a unit of power that signifies the rate at which work is done or energy is transferred, while amps (short for amperes, named after the French physicist André-Marie Ampère) measure electrical current. The conversion between these units requires additional parameters like the motor's efficiency, power factor, and the supplied voltage. This tutorial elucidates these calculations and associated formulas.

Convert Electric Motor Hp to Amps Calculator
Horsepower to Amps Unit Calculator Results
1 Ph. Ampere = A
1 Ph. FLA = A
3 Ph. Ampere = A
3 Ph. FLA = A

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Example Formula

To convert horsepower to amps, the following formula can be used:

I = (P × 746) / (Eff × PF × V)


  1. I: Represents the current in amps.
  2. P: Represents the power in horsepower.
  3. Eff: Represents the motor efficiency (in percentage).
  4. PF: Represents the power factor (ranges between 0 and 1).
  5. V: Represents the voltage in volts.

The factor 746 in the formula is used to convert horsepower to watts, as 1 horsepower equals 746 watts.

Who wrote/refined the formula

This formula is not attributed to a specific individual but has been developed over time as our understanding of electrical engineering has grown. It's a practical calculation widely used in electrical engineering, maintenance, and design. It's also essential for calculating the sizing of electrical circuits and ensuring safety and efficiency.

Real Life Application

This formula is frequently used when installing a new electric motor or generator to determine the correct wiring and circuit breaker size to handle the expected current load. For example, a maintenance engineer in an industrial plant might use this formula when installing a new motor to drive a conveyor belt.

Key individuals in the discipline

While not directly linked to the development of the formula, James Watt, a Scottish inventor, and Michael Faraday, an English scientist, made significant contributions to the understanding of electrical power and current. Watt developed the concept of horsepower, while Faraday's experiments with electricity led to the understanding of electromagnetic fields.

Interesting Facts

  1. This formula's importance extends to everyday life, contributing to the safety and efficiency of electrical appliances in our homes. Correctly sized wiring and circuit breakers prevent overloading and potential electrical fires.
  2. The concept of horsepower was initially invented to compare the power output of steam engines with the power of draft horses.
  3. Improving motor efficiency is a major factor in reducing global electricity consumption and promoting sustainability.


Understanding how to convert electric motor horsepower to amps is a critical skill in electrical engineering. This knowledge aids in the safe and efficient operation of electric motors, contributing to overall energy conservation.

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