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Horsepower Formula

Last updated date: 17th Apr 2024
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What is Horsepower?

Horsepower (HP) is a unit of measurement for power, or the rate at which work is completed, usually in relation to the engine or motor output. There are a variety of horsepower specifications and types. Mechanical horsepower (or imperial horsepower), which is roughly 745.7 watts, and the metric horsepower, which is about 735.5 watts, are two typical definitions used today.

Scottish engineer James Watt coined the word in the late 1800s to relate the output of steam engines to the power of draught horses. Later, it was broadened to cover the output power of various types of piston engines, as well as turbines, electric motors, and other machinery. The definition of the unit differed depending on where you were. For the measurement of electricity, most countries today utilise the SI unit watt. Since the adoption of EU Directive 80/181/EEC on January 1, 2010, horsepower can only be used as a supplemental unit in the EU.

Horsepower Definition Science

Horsepower is defined as the work done per unit time and this term was invented by James Watt. It is a unit of power that relates a machine's power to the muscle power of a horse. It was once used to compare the output of steam engines to the power of draught horses. It was later expanded to include other piston engines, electric motors, turbines, and other machinery.

Horsepower Meaning - The power of an engine measured in terms of horsepower, where one horsepower is equal to about 750 watts.

One Horsepower equals 33,000 lb. ft/min.

Horsepower (HP Formula) is Given as:

HP = (Torque Speed)/5252.

Another Horsepower formula related to the weight is represented as,

Horse Power = Weight x \[(\frac{Velocity}{234})^{2}\]

Solved Examples 

1. Calculate the Horsepower of an Automobile That Spins at 600 Rpm and has a Torque of 100 Pound-Foot.


Given parameters are

Torque = 100 pound-foot

Speed = 600 revolutions per minute>

Horsepower (hp formula) is given by

Horsepower = (Torque × Speed) / 5252

HP = (100 × 600) / 5252

HP = 60000/5252

HP = 1.142 hp

2. Calculate the Vehicle's Speed If it has 0.865 Horsepower and 250 Pound-Foot of Torque.


Given parameters are

Torque = 250 pound-foot

Horsepower (hp) = 0.865 hp

The speed is given as

Speed = (Horsepower × 5252)/ Torque

Speed = (0.865 × 5252)/ 250

Speed = 4542.98/250

Speed = 18.17 revolutions per min

3. Calculate the Horsepower of a Vehicle That Rotates at 500 Rpm and has a Torque of 100 Pound-Foot.


Given parameters in the problem are:

Torque = 100 pound-foot

Speed = 500 revolutions per minute

We may now use the Horsepower formula as follows:

Horsepower =  (Torque×Speed)/5252

Substituting the known values, we get

Horsepower =  (100×500)/5252

= 50000/5252

Horsepower = 9.52 HP

As a result, the vehicle's engine will produce 9.52 horsepower.

FAQs on Horsepower Formula

1. What is 1HP Equal To?

Answer. A horsepower (hp) is roughly comparable to 746 watts (W) or 0.746 kilowatts (kW). Multiply by 746 to convert horsepower to watts.

2. How to Calculate Horsepower Physics?

Answer. Power = (Force x Distance) / Time

The equation to calculate horsepower is simple: Horsepower = Torque x RPM / 5,252. There are also some horsepower calculators available to calculate the horsepower.

3. What Do the Engine Horsepower Formula Refers To?

Answer. The term "horsepower" refers to the amount of power produced by an engine. It's computed by multiplying the power required to move 550 pounds one foot in one second by 33,000 pounds one foot in one minute. The rate at which the work is completed is used to determine the power.