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12 conversions · 4 units
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Welcome to the ConvertNow power converter hub. Whether you are a student solving homework, a professional completing a project, or a traveller navigating unfamiliar units, our free power conversion tools give you instant, accurate results backed by internationally verified constants.
Power — the rate of doing work — was formalised when James Watt rated his steam engines against the work of horses in the 1780s, giving us the horsepower: the power to lift 550 pounds one foot in one second. The watt, named for him a century later, became the SI unit. Metric horsepower (PS) was defined separately in continental Europe as 75 kilogram-force metres per second, which is why hp and PS figures for the same engine never quite match.
Power conversion shapes car buying, EV comparison, and machinery specification. Electric motors are rated in kilowatts while many buyers still think in horsepower — a 150 kW EV motor is about 201 hp. A generator or compressor specced in the wrong unit is underpowered for the job it was bought to do.
Automotive engineers, EV buyers, electricians, HVAC technicians, and machinery operators.
Mechanical horsepower (hp) vs metric horsepower (PS): 1 hp = 1.014 PS, so a European spec sheet reads slightly higher for the same engine. Also, the kilowatts on an EV badge are power, not stored energy — battery size is kilowatt-hours (kWh).
| Unit | Symbol | Base Equivalent | Common Use |
|---|---|---|---|
| Watt | W | SI unit | Worldwide |
| Kilowatt | kW | 1,000 W | EVs, electricity |
| Horsepower | hp | 745.7 W | US/UK engines |
| Metric Horsepower | PS | 735.5 W | European cars |
| Common Value | Equals |
|---|---|
| 1 hp | 0.746 kW |
| 100 kW | 134.1 hp |
| 1 PS | 0.986 hp |
| 200 hp | 149.1 kW |
One mechanical horsepower is 0.7457 kilowatts (745.699872 watts — it was defined as 550 foot-pounds per second). Multiply hp by 0.7457 to get kW: a 300 hp engine is about 224 kW.
They are two different horsepower definitions. Mechanical horsepower (hp, used in the US and UK) is 745.7 W; metric horsepower (PS, used in continental Europe) is 735.5 W — about 1.4 % smaller, so the same engine shows a slightly higher number in PS.
The kilowatt is the SI unit of power, and the natural unit for electric motors. Multiply kW by 1.341 to get the horsepower figure most buyers are used to: a 200 kW motor makes about 268 hp.
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