November 7, 2025, 9:43 am | Read time: 3 minutes
If you want to show off your car, you often talk about its horsepower. The higher the number, the faster the car usually is. But how much horsepower does a horse actually have? Spoiler: The answer isn’t always one.
Most of us associate the term “horsepower” with cars—even complete car novices. However, the term has an animal origin. This raises the question: How much horsepower does a horse actually have? To answer this question, a historical excursion is necessary.
Why Is It Called Horsepower?
We are in the late 18th century—a time when there are no cars yet. The Englishman James Watt designs a steam engine that is more efficient than previous models. Naturally, he wants to sell it. But he lacks a good marketing strategy.
Then Watt comes up with a solution: At the time, horses were often used as draft animals. So why not compare the power of the steam engine to the work performance of horses?
With this goal in mind, the inventor observed the animals at work and collected data. He concluded that a horse could lift 330 pounds (about 150 kilograms) 100 feet (about 30 meters) in one minute. James Watt called this value “horsepower.”
Incidentally, the unit of measurement “watt” is also named after the British inventor. According to the original definition, one horsepower is approximately 746 watts. With the introduction of the metric system, the value of horsepower was slightly changed, and it now equals about 735 watts.1
Also interesting: Why Some Horses Have a Mustache
How long do horses live?
Why Horses in the Middle Ages Were Much Smaller Than Thought
How Much Horsepower Does a Horse Have?
According to Watt’s calculation, a horse would have one horsepower. A theory confirmed by British veterinarian William Youatt a few years later. According to the BBC magazine “Science Focus,” Youatt visited a fair in the U.S. state of Iowa in 1925 and analyzed the average performance of workhorses per day.
James Watt already knew that a horse’s performance could vary greatly. Breed, age, and condition of the animal: All these factors can influence horsepower. As biologists Stevenson and Wasserung wrote in the journal “Nature” in 1993, a horse could theoretically reach 24 horsepower due to its muscle strength. At least for a short time.
Practically speaking, the number is somewhat lower. Racehorses, for example, can reach almost 15 horsepower.
For comparison: According to a Statista analysis, the highest “average horsepower of cars in Germany by state in 2024” was in Bavaria with 139.3 horsepower. The most powerful cars in the world even reach the thousands. Since 2010, however, a car’s horsepower can only be specified in conjunction with the internationally standardized unit kilowatt.
Do People Still Say Horsepower?
Although watt is actually the official designation of the physical unit, people often still colloquially refer to horsepower. In common usage, horsepower is mainly associated with cars, which is why you occasionally still see horsepower figures in car advertisements.
The question of how much horsepower a horse really has spans an exciting arc: from the invention of the steam engine to the physical fundamentals to our modern understanding of power and speed.2