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Talking about horsepower usually means engines

You don’t necessarily have to sat on a horse to know that these creatures are strong. And that’s what James Watt took advantage of more than 200 years ago. He is considered the inventor of the steam engine. But he is not. Thanks to the improvements made by James Watt, however, the steam engine can work efficiently. And that’s exactly what he wants to measure: performance. The performance of machines. James Watt doesn’t choose an abstract unit to show what a steam engine can do. He uses what people knew at the time: the strength of a horse.

Named after the average performance of a workhorse

James Watt defines the performance of a horse as follows: It is the power when a horse raise 330 pounds of coal 100 feet in a minute – according to James Watt, that means 1 horsepower.


As workhorses, horses were used everywhere in his time. This is also the case in mills and mines. And what does James Watt want? The operators of mines should very easily calculate how many horses they can replace with a steam engine. And for that he needs a unit of measurement.

So James Watt invents the term horsepower to illustrate the power of his new steam engine. For him, it doesn’t matter that horses are of course of different strengths. A heavy cold-blooded horse certainly has more power than a fine thoroughbred. Horsepower is not the same as horsepower. However, he is not concerned with maximum strength, but with the average guidance of a workhorse.


If a horse exceeds the power defined by Watt, for example in a short time in a competition, then it also has more than one horsepower. On average, however, it delivers one horsepower.

James Watt invents a unit of measurement for a machine's performance

Its improvements helped the steam engine break through, the industrial revolution began. For many car buyers, the horsepower specification is still an important decision criterion. Because the horsepower indicates the power of the engine. You can imagine the picture when a car with 150 horsepower is pulled by 150 horses. But as strong as 150 horses may be together, the high speeds like those of a powerful car will not reach them. Data for engines are meanwhile given in watts or kilowatts. As the name suggests, this unit is named after the Scotsman James Watt, but was not established until the 20th century. Both specifications can be found in the technical data of a vehicle. And everything is based on the real workforce of horses.