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Motor power is quoted in kilowatts (kW) in most of the world and in horsepower (hp) in North America and on many older machines. There are two horsepower definitions: mechanical / electric horsepower equals exactly 745.7 W, and metric horsepower (PS or CV) equals 735.5 W. They differ by about 1.4%, so it matters which one a nameplate uses.
| Conversion | Formula |
|---|---|
| Mechanical hp → kW | kW = hp × 0.7457 |
| Metric hp (PS) → kW | kW = hp × 0.7355 |
| kW → mechanical hp | hp = kW / 0.7457 = kW × 1.341 |
| kW → metric hp | hp = kW / 0.7355 = kW × 1.360 |
A quick rule: 1 kW ≈ 1.34 hp, and 1 hp ≈ 0.75 kW. For motors, always convert the output (shaft) power — the input electrical power is higher by the efficiency factor.
Multiply mechanical horsepower by 0.7457 to get kilowatts (1 hp = 745.7 W). For metric horsepower (PS) multiply by 0.7355 instead.
Divide kilowatts by 0.7457 for mechanical horsepower, which is the same as multiplying by 1.341. For metric horsepower, divide by 0.7355 (or multiply by 1.360).
Mechanical (or electric) horsepower is 745.7 W, while metric horsepower (PS or CV) is 735.5 W. They differ by about 1.4%, so the definition used affects the exact kW value.
One mechanical horsepower is 745.7 watts, and one metric horsepower is 735.5 watts. Both are close to three-quarters of a kilowatt.
Almost. 10 mechanical hp is 7.46 kW, which is commonly rounded to the standard 7.5 kW motor frame. The two ratings are used interchangeably in practice.
PS (Pferdestärke) and CV (cheval-vapeur) are names for metric horsepower, equal to 735.5 W. They are common on European vehicles and machinery; 1 PS = 1 CV.
For motors, horsepower and kW ratings refer to the mechanical output (shaft) power. Convert that figure directly. The electrical input power is higher by the efficiency factor and is a separate calculation.
Remember 1 kW ≈ 1.34 hp and 1 hp ≈ 0.75 kW. These are accurate to about 1% and are handy for quick mental estimates.
US and other imperial-market motors use mechanical (electric) horsepower of 745.7 W. European nameplates that show PS or CV use metric horsepower of 735.5 W.
1.5 kW is about 2.01 mechanical hp (1.5×1.341) or 2.04 metric PS. It is typically marketed as a 2 hp motor.
No. It is only a change of units for the same physical power. A motor rated 10 hp and one rated 7.46 kW describe the same output.
International standards define preferred power ratings (0.75, 1.1, 1.5, 2.2, 3, 4, 5.5, 7.5 kW…), which happen to line up closely with common horsepower values, so the two systems map neatly onto each other.
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