How Do You Measure a Horse’s Horsepower?
by Ashley Dreiling
It may come as a surprise that a horse has much more potential than just a single. In fact, estimates suggest that in full gallop, a horse can produce between 12 and 14.9 horsepower.
Horsepower (hp) is a unit of measurement first developed around 1780 by Scottish engineer James Watt to compare the energy of steam engines to a workhorse. Watt sold steam engines and was looking for a way to demonstrate the advantage of a steam engine’s speed compared to the work rate of horses.
Horsepower is the amount of power required to move 550 pounds by one foot in one second, approximately equal to 745 watts. Today, hp is primarily used to gauge the power of a car’s engine, but it is possible to apply it to the power potential of an animal, such as a horse.
Watt’s calculations were based on a single horse pulling a mill wheel for four hours, to find that a horse pushing around 550 pounds by one foot in one second. However, this number reflects a full day’s work and not a horse’s full potential.
In 1993, scientists published a paper in Nature that showed the peak mechanical power output of a horse is actually between 12 and 14.9 horsepower. Their estimation was based on a horse’s skeletal muscle, which is about 45 percent of its total mass. If they usually use 30 percent of this while running, a horse at full gallop could produce more power.
Cars are still your most powerful choice, typically operating between 180 and 200 horsepower.