A worked example: 1 horsepower to kilowatts
1 mechanical horsepower converts to 0.7457 kilowatts — the standard conversion used for vehicle engine ratings in most English-speaking markets.
The formula: convert through watts
Converted value = amount × (from-unit-to-watts factor) ÷ (to-unit-to-watts factor), the same through-a-common-unit pattern used for any physical quantity conversion — watts is simply the SI reference point every other power unit is defined against.
Mechanical horsepower vs. metric horsepower (PS): a worked contrast
1 metric horsepower (PS) — the unit commonly used in Indian and European vehicle brochures — converts to 0.735499 kW, slightly less than mechanical horsepower's 0.7457 kW. The two units are close enough to blur together but different enough that comparing a US-spec horsepower figure directly against a PS figure understates the US engine's actual power by about 1.4%.
Scaling up: 1 megawatt to watts
1 megawatt converts to exactly 1,000,000 watts — the same "mega" prefix used across SI units, applied here to a quantity large enough to describe a power plant's output rather than an appliance's.
Why checking which horsepower a spec sheet uses matters
Before comparing two vehicles' power figures, check whether both specs use the same horsepower definition — a manufacturer publishing PS figures next to a competitor's hp figures would otherwise make the PS-rated vehicle look weaker than it actually is, purely from the unit difference rather than the engines themselves.