Power measures how fast work is done or energy is transferred. In SI units, the base expression is the watt: 1 W = 1 J/s. Motors, pumps, compressors, generators, and vehicle drivetrains all use power to describe output or consumption over time.
W, kW, and MW are decimal multiples of the same SI quantity. 1 kW = 1000 W and 1 MW = 1000 kW. Small electronics may stay in watts, industrial motors often sit in kilowatts, and large utility or plant systems move into megawatts.
Horsepower is older and more common in product marketing, but it is not a single universal standard. This page distinguishes mechanical horsepower (hp) from metric horsepower (PS), and the difference matters whenever you compare catalogs from different regions.
The conversion itself is linear. The tool converts your input to a base watt value and then divides by the target unit factor. That is why power conversion is well suited to instant browser-side calculation.
What unit conversion does not solve is meaning. Rated power, peak power, continuous power, shaft power, input power, and output power are different technical concepts. Confirm the field definition first, then convert the unit.