Horsepower Calculator
Calculate horsepower and convert between different power units
Horsepower Calculator
Horsepower is a measurement of power, or the rate at which work is done. This calculator can be used to compute horsepower according to its definition and to convert between different power units.
Quick Navigation
𧎠Horsepower Calculation Based on Definition
đ Result
It is equivalent to:
đ Horsepower Converter
Converts between different units of power.
Conversion Result
đ Understanding Horsepower
What is Horsepower?
Horsepower is a unit of measurement of power developed by engineer James Watt in the late 18th century. Although its original purpose was to compare the output of steam engines with the power of horses, it has since been adopted for all sorts of engines.
Modern Applications
Horsepower is commonly used today to refer to the potential work output of a vehicle's engine, and is widely cited for performance comparisons of vehicles, lawn mowers, boats, chainsaws, and airplanes.
Power vs Energy
Power is the rate at which work is done or energy is transferred. Horsepower measures how quickly work can be performed, while energy measures the total amount of work that can be done.
Different Types of Horsepower
When the term horsepower is used, people are probably referring to mechanical horsepower. However, there are other lesser known definitions of the word.
Mechanical Horsepower, hp(I)
550 foot-pounds per second, approximately 745.7 watts. The most common definition of horsepower, mechanical horsepower, is the horsepower James Watt invented in 1782.
Metric Horsepower, hp(M)
75 kgf-m per second, approximately 735.499 watts
Boiler Horsepower, hp(S)
34.5 pounds of water evaporated per hour at 212 degrees Fahrenheit, approximately 9,809.5 watts. This definition is mainly used to denote a boiler's capacity to deliver steam to a steam engine.
Electrical Horsepower
746 watts. This definition is mainly used for electrical machines.
Units and Conversions
Horsepower is not recognized in the International System of Units (SI); SI uses a measurement of power called a watt, which is named after James Watt. A watt is defined as one joule per second and is generally used to quantify a rate of energy transfer for lower rates of power consumption such as lightbulb or smartphone charging.