An average horse can produce about 15 horsepower in short bursts and sustain around 7 to 8 horsepower over longer periods. Specifically, studies show that a horse can briefly reach up to approximately 14.9 horsepower and maintain about 7.3 horsepower for extended durations

. This means the common notion that a horse has exactly one horsepower is a simplification. The unit "horsepower" was originally defined by James Watt in the 18th century to compare steam engine power to the work a horse could do over a long period, but actual horses can generate much more power momentarily

. The exact horsepower varies depending on the horse's breed, size, fitness, and the type of exertion, with draft horses capable of exceeding the theoretical one horsepower during peak effort