Metric horsepower to Milliwatts Converter

Metric horsepower (PS). Metric horsepower (PS) is 735.49875 watts, used for vehicle engine ratings across much of Europe and Asia. It is slightly smaller than mechanical horsepower.

Milliwatts (mW). A milliwatt is one thousandth of a watt. It is used for small electronics, radio transmission power and laser pointers; an indicator LED draws a few milliwatts.

Metric power conversions are exact. Check whether a horsepower figure is mechanical or metric before comparing two engines.

Within the metric units a power conversion is a power of a thousand: watts to kilowatts, kilowatts to megawatts, and back. Those pairs are decimal shifts and a reader can do them without a converter.

Anything involving horsepower is a multiplication by a definition rather than a shift, and there are two definitions. Mechanical horsepower is exactly 745.7 watts and metric horsepower exactly 735.49875 watts, so the same engine carries a larger figure in mechanical horsepower than in metric.

When checking a power conversion, convert to watts first, because every unit in this dimension is defined against the watt and the intermediate value makes the comparison obvious. The trap is comparing a horsepower figure with a kilowatt figure without establishing which horsepower was quoted.