HP to kW Calculator

Convert horsepower (HP) into kilowatts (kW) using our straightforward calculator with efficiency and power factor inputs.

Conversion Inputs

How to Convert Horsepower (HP) to Kilowatts (kW)

Horsepower (HP) and kilowatts (kW) are both units of power, but they measure it in different ways. HP is a mechanical unit of power, while kW is an electrical unit. Converting HP to kW is essential when sizing generators, motors, or other equipment that involves mechanical and electrical systems.

Key Differences Between HP and kW

  • Horsepower (HP): A unit of mechanical power output, commonly used for engines and motors. 1 HP = 746 watts.
  • Kilowatts (kW): A unit of electrical power output or input, equal to 1000 watts.

Formula to Convert HP to kW

The formula for converting HP to kW is:

kW = (HP × 746) ÷ (Efficiency × 1000)

Where:

  • HP: Horsepower
  • 746: Watts per HP
  • Efficiency: Decimal value between 0 and 1 (e.g., 0.9 for 90% efficiency)

Example:

Convert 50 HP to kW with an efficiency of 90%:

kW = (50 × 746) ÷ (0.9 × 1000)
    = 37300 ÷ 900
    ≈ 41.44 kW

In this example, 50 HP is approximately equal to 41.44 kW.

Efficiency and Why It Matters

Efficiency measures how much of the input energy is converted into useful output work. Lower efficiency means more energy is wasted as heat or other losses, requiring more power input to achieve the desired output.

Most motors and engines have efficiency values ranging from 85% to 95%. Always include efficiency in your calculations to get accurate results.

Applications of HP to kW Conversion

  • Specifying generator sizes for motors
  • Calculating electrical demand for industrial equipment
  • Converting mechanical energy to electrical energy

FAQ

Is HP the same as kW?

No, 1 HP is equal to 0.746 kW. HP measures mechanical power, while kW measures electrical power.

Can I convert HP to kW without efficiency?

If efficiency is unknown, assume a typical value (e.g., 0.85 or 0.9), but the result will be less accurate.

Conclusion

Converting HP to kW is a critical step in sizing electrical systems for mechanical loads. Use the calculator above for quick and accurate conversions, and always account for efficiency to avoid errors in your calculations.