How Much Horsepower Does a Horse Have? How Is It Calculated?

How much horsepower does a horse have?

This word is probably familiar from its typical use as a measure of engine power for cars, but it can be applied to horses too.

Here, I will explain what I’ve learned about what a unit of measure is for this type of power, determine the amount that a typical horse has, and compare it to humans and cars.

READ ON!

What is Horsepower?

black horses working on the farm

According to Merriam-Webster Dictionary, the definitions of horsepower are “the force that a horse exerts in pulling” or “a unit of power equal to 746 watts” (1)

But before the question of “how much horsepower does a horse have?” can be answered in more detail, we have to understand more about what horsepower is.

One thing is certain, it is not related to horse mating. So when is this unit of power used?

Horsepower is usually applied to describe the power output of engines, but it can also be used for boat engines, train engines, and other modes of transportation.

Here is a video that explains more about horsepower:

Why is it Called Horsepower?

Horsepower got its name because the people who were working on steam engines needed to know how many horses would be replaced by the output of steam engines.

Before the invention of the steam locomotive, horses were the primary mode of transportation and were responsible for delivering cargo across the country.

When the first steam engine was introduced, people were wary of how effective it would be. So, horsepower was created as a measurement of power to show off its capability.

READ MORE: Can a Horse Carry a 200-pound Person?

Who Invented Horsepower?

The term horsepower was invented by James Watt, an engineer who invented steam engines as we know them today, in the 18th century.

He created the unit to sell his improved steam engine to people. The best way to do this was to compare it to horses because horses were all people knew.

He wanted to prove the power of steam engines using this new unit of measurement.

If you want to learn more about James Watt, check out this video.

How Is Horsepower Calculated?

The unit of horsepower is calculated using an equation: hp= F/dt. Where hp is horsepower, f is the force in pounds, d is the distance in feet, and t is time in minutes or times per minute.

This calculation was created because James Watt spent time observing horses that worked at a mill. They were tied to spokes on the mill’s central shaft and walked around it to make it work.

The horses walked around the mill in a circle 24 feet in diameter, 144 times in an hour. It was estimated that each horse was pulling a force of 180 pounds. 

How Much Horsepower Does 1 Horse Have?

brown horse pulling a cart

One horse can have an output of 14.9 horsepower, but this varies depending on the type of horse because the measurement was made using draft horse power. Draft horses are the strongest horse.

Arabian horses or lighter horses will have less horsepower than the power of draft horses because they have less strength and musculature than drafts do.

According to the findings noted by Watt above, he calculated that the average horse could do 33,000 foot-pounds or hoofbeats of work in one minute. This is what a single horsepower is equal to.

The aforementioned 33,000 foot-pounds can also equal 550 foot-pounds or hoofbeats per second or 745.7 watts of power per second. 

Prior to finding this calculation,  R. D. Stevenson and Wassersug did a study to find out how much horsepower horses could pull that was published in Nature (2).

They found that horses could pull 18,000 watts or 24 horsepower, which was not an accurate real-world finding.

Stevenson and Wassersug re-did their study at the 1975 Iowa State Fair and found that a horse could exert a maximum of 14.9 horsepower, which is the metric referred to today.

Horses do not generate 1 horsepower every time they do work or pull something. This number will vary slightly depending on horse fitness, conformation, and the length and intensity of their work.

However, horsepower is not equal to the weight limit horses can carry. Horses can carry about 20% of their body weight without risking spinal damage (3).

Hopefully, that answers the question ‘how much hp does a horse have?’ Now that we know about horsepower in horses, let’s look at humans.

How Much Horsepower Does a Human Have?

How much horsepower does a healthy human have? Yes, humans can generate horsepower. However, there is not an exact figure for this.

If we look at power in general, the average human uses 100 to 150 watts a day to keep their body running.

From this, it can be estimated that each human gives off 15 to 20 horsepower daily. This is a lot less than a car, as you’ll see next.

What is the Average Horsepower of a Car?

blue car on the road

The average horsepower for a car lies anywhere between 180 and 200. Horsepower is not directly related to the speed of a car.

The best car horsepower is between 200 and 300, although this is typically seen in higher-end cars.

To find the horsepower in a car engine, use the equation hp= torque x speed. You can also check the engine and see how many cylinders it has. 

More cylinders mean more horsepower.

However, the average range of horsepower varies depending on the size of the car. A crossover has an average of 200 horsepower, a midsize car has an average of 170 horsepower, and a small SUV has an average of 240 horsepower.

Bigger cars need more power because they are heavier and need more energy. However, horsepower that is greater than 300 can be dangerous for inexperienced drivers.

This is due to the lack of control and lack of stopping ability when needed that driving at high speed and power comes with.

FAQs

Does horsepower make a car faster?

Horsepower does not make a car faster because it is not directly related to the speed of a car.

How many horses does it take to make 1 horsepower?

Only one horse is necessary to make 1 horsepower. One horsepower is 745.7 watts produced by one horse.

Does one horsepower really equal the power of one horse?

Cathy Benscoter Horse

Contrary to popular belief, a single horse can produce up to 14.9 or 15 horsepower. It is a common misconception that one horse only produces one horsepower.

Conclusion

Horsepower was invented by engineer James Watt after he needed to show the public how many horses his new steam powered engines could replace. It is calculated using the formula hp=F/dt.

So, to answer “how much horsepower does a horse have?” is that that a horse can pull, equal to 745.7 watts.

black horse pulling a cart

What do you think about horsepower?

References

  • 1. Definition of HORSEPOWER [Internet]. www.merriam-webster.com. [cited 2022 Jul 14]. Available from: https://www.merriam-webster.com/dictionary/horsepower#:~:text=Definition%20of%20horsepower
  • 2. Stevenson RD, Wassersug RJ. Horsepower from a horse. Nature. 1993;364:195–5.
  • 3. Guidelines for weight-carrying capacity of horses [Internet]. extension.umn.edu. Available from: https://extension.umn.edu/horse-care-and-management/guidelines-weight-carrying-capacity-horses
Siun L
Siun L

Siun is an all-around animal lover, with a passion for horses. She grew up in the United States, competing in the hunters, equitation, and jumpers. Now living in Ireland, she competes with her own showjumping horses. She is experienced in the care and training of horses, as well as teaching riding lessons. She loves to combine her love for horses with her work. When not working, Siun will be found at the stables, rain or shine.
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