How to Convert kW to Horsepower (hp)

This calculator converts power from kilowatts (kW) to horsepower (hp) using the standard mechanical horsepower definition. Enter the power in kilowatts, and you’ll get the equivalent in horsepower instantly. It also shows the conversion for metric horsepower, which is sometimes used in Europe.

Formula

The conversion between kilowatts and mechanical horsepower is straightforward:

hp = kW × 1.34102209

Where:

• hp = power in mechanical horsepower (hp)
• kW = power in kilowatts (kW)
• 1.34102209 = the conversion factor (exact: 1 hp = 0.745699872 kW)

For metric horsepower (PS, or cv), the factor is different:

hp_metric = kW × 1.359621617

Where 1 metric hp = 0.73549875 kW.

Worked Example

Using the default value of 100 kW:

1. Multiply 100 kW by 1.34102209: 100 × 1.34102209 = 134.102209
2. Round to two decimal places: 134.10 hp (mechanical)
3. For metric hp: 100 × 1.359621617 = 135.9621617, rounded to 135.96 hp (metric)

So 100 kW equals approximately 134.10 mechanical horsepower or 135.96 metric horsepower.

When to Use This Conversion

Kilowatts are the standard unit for electrical power and are used for electric motors, generators, and in most countries for vehicle engines. Horsepower is still common in the US, UK, and for describing engine output in many contexts. You’ll need this conversion when:

• Comparing electric motor specs (kW) to gasoline engine specs (hp).
• Reading vehicle specifications from different markets.
• Sizing generators or pumps where both units appear.

How to Read the Result

The result gives you the equivalent power in horsepower. For example, a 150 kW electric motor produces about 201 hp. Remember that this is mechanical horsepower (the most common type in the US). If you’re dealing with metric horsepower (often called PS or cv), use the second output. Always check which type of horsepower your application expects.

Common Mistakes

• Using the wrong horsepower type: Mechanical hp (1 hp = 0.7457 kW) vs. metric hp (1 PS = 0.7355 kW). Mixing them causes about 1.4% error.
• Rounding too early: If you round the conversion factor to 1.34, you’ll get 134 hp instead of 134.10. For precise work, keep more decimals.
• Confusing kW with kWh: kW is power (rate of energy use), kWh is energy (total amount). This conversion only applies to kW.

Tips

• For quick mental estimates, multiply kW by 4 and divide by 3 (since 1.34 ≈ 4/3). For 100 kW: 100 × 4 / 3 = 133.3 hp (close to 134.1).
• When comparing electric motors, remember that electric motors often have higher efficiency than combustion engines, so a lower hp electric motor may perform similarly.
• If you need boiler horsepower (used for steam boilers), the factor is different: 1 boiler hp = 9.8095 kW. This calculator does not handle that.

Troubleshooting

If the result seems off:

• Check that you entered the power in kilowatts, not watts (1 kW = 1000 W). If you entered 100,000 W, you’d get 134,102 hp, which is incorrect.
• Verify you’re not accidentally using the metric output when you need mechanical hp. The two differ by about 1.4%.
• If you’re comparing to a manufacturer spec, confirm which horsepower standard they used. Some use ‘PS’ (metric), others use ‘bhp’ (brake horsepower, which is mechanical).

Frequently Asked Questions

What is the difference between kW and hp?

Kilowatt (kW) is the SI unit of power, defined as 1000 watts. Horsepower (hp) is an imperial unit originally defined as the power a horse could sustain. 1 hp = 0.7457 kW, so kW is a larger unit.

Why are there different types of horsepower?

Historically, different regions and industries defined horsepower slightly differently. The most common are mechanical hp (used in the US), metric hp (PS, used in Europe), and electrical hp. They differ by a few percent.

How many kW is 1 hp?

1 mechanical horsepower equals 0.745699872 kW. For metric horsepower, 1 PS = 0.73549875 kW.

Can I convert kW to hp for electric motors?

Yes, the conversion is the same. However, note that electric motor output is often rated in kW, and the hp equivalent is mechanical hp. The actual mechanical power delivered by the motor shaft is what the conversion represents.

Is BHP the same as hp?

BHP (brake horsepower) is a specific measurement of engine power at the crankshaft, excluding losses from the gearbox and drivetrain. It is numerically the same as mechanical hp for the same measurement. In practice, BHP is often used interchangeably with hp.

How do I convert hp back to kW?

Simply divide by the conversion factor: kW = hp / 1.34102209. Or multiply by 0.745699872.

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in kw | Power (kW) | kW | 100 | 0
out hp_mech | Horsepower (mechanical) | hp | kw * 1.34102209 | 2
out hp_metric | Horsepower (metric) | hp | kw * 1.359621617 | 2