Convert kW to HP
kW to HP Converter
Convert Kilowatts to Horsepower (Mechanical, Metric, or Electrical).
Report Bug For over a century, the United States has measured power in Horsepower (HP). But with the rise of Electric Vehicles (EVs), the global standard of Kilowatts (kW) is taking over. The kW to HP Converter solves the confusion on the dealership floor. It translates the scientific output of an electric motor into the "Muscle" terminology Americans understand.
Whether you are sizing an industrial air compressor or comparing a Hyundai Ioniq 5 to a Ford Mustang, accurate power conversion is the only way to gauge real performance.
⚙️ The Engineer's Constant (SAE Standards)
In the US and UK, we use "Mechanical Horsepower" (Imperial). The rest of the world often uses "Metric Horsepower" (PS or CV). The conversion factors are slightly different:
(1 HP = 745.7 Watts)
Key Distinction:
- Mechanical HP (US): The standard for US car marketing.
- Metric HP (PS): Used in Europe. (1 kW = 1.36 PS).
- Electrical HP: Generally considered equal to Mechanical HP for motors.
🏎️ Scenario: The EV Spec Sheet Decoder
You are looking at a new EV listed with a 150 kW electric motor. How does this compare to your old 200 HP gas sedan?
Technical Insight: While the peak HP might be similar, Electric kW feels faster because electric motors deliver 100% of their torque instantly (0 RPM), whereas gas engines need to rev up to reach their peak HP.
US Industrial & Automotive Standards
- SAE J1349: This is the official US standard for measuring "Net Horsepower" at the crankshaft with all accessories (alternator, water pump) attached. This is what you see in brochures.
- NEMA Motors: In the US industrial sector, electric motors are still labeled in HP (e.g., a "5 HP Compressor"). However, their efficiency calculations and power bills are calculated in kW.
- The "Brake" in BHP: Brake Horsepower refers to the device (a prony brake) used to measure the engine's power by applying a load to it. In modern US usage, BHP and HP are often used interchangeably for Net power.
Frequently Asked Questions (FAQs)
Why is 1 HP equal to 746 Watts?
James Watt defined 1 Horsepower as the ability of a horse to lift 33,000 pounds by one foot in one minute. When converted to standard SI units (Joules per second), this equals approximately 745.7 Watts.
What is the difference between HP and kW in charging?
Be careful! Motor Power is output (HP or kW). Charging Speed is input (measured only in kW). A Tesla Supercharger might deliver 250 kW of charging speed, but that has nothing to do with the car's 300 HP motor.
Is Metric HP (PS) the same as US HP?
No. Metric HP (Pferdestärke) is slightly "weaker."
1 Mechanical HP (US) = 1.014 Metric HP (EU).
A car rated at 500 PS in Germany is only about 493 HP in the US.
How do I convert kW to Amps?
You cannot convert directly without knowing the Voltage. The formula is Amps = (kW × 1000) / Volts. For 3-phase motors, you also need the Power Factor.
Why do EVs use kW instead of HP?
Because electricity is natively measured in Watts and Amps. Using HP for a battery-powered device requires an unnecessary conversion. However, US marketing still uses HP because consumers associate it with speed and performance.
