Power Units
Convert between watts, kilowatts, horsepower, and BTU/h.
Engines & Motors
Perfect for automotive, electrical, and mechanical power calculations.
Scientific Accuracy
Precise conversions for engineering and energy applications.
Understanding Power Conversion
Power measures the rate of energy transfer or work done per unit time. The SI unit is the watt (W), defined as one joule per second. Different industries use different units: watts/kilowatts in electrical systems, horsepower in automotive, and metric horsepower (PS/CV) in European vehicle specifications.
One mechanical horsepower equals approximately 745.7 watts, while one metric horsepower (PS, Pferdestärke) equals about 735.5 watts. Kilowatts are commonly used for electric motors and power plants (1 kW = 1,000 W). Understanding these conversions is essential for comparing engine specifications, electrical appliances, and industrial machinery.
Common Usage Examples
- Automotive: Comparing engine power across different markets
- Appliances: Understanding electrical consumption in watts
- Solar Energy: Panel output and system capacity
- Renewable Energy: Solar panel and wind turbine output
- HVAC: Air conditioner and heater power consumption
- Engineering: Power calculations for mechanical systems
Frequently Asked Questions
How do I convert horsepower to kilowatts?
Multiply horsepower by 0.7457. For example, 100 HP × 0.7457 = 74.57 kW. This is useful for comparing US and European vehicle specifications.
What's the difference between HP and PS?
HP (horsepower) is the imperial unit (745.7 W), while PS (Pferdestärke) is the metric horsepower (735.5 W). PS is slightly smaller, so 100 PS ≈ 98.6 HP.
How many watts are in a kilowatt?
There are exactly 1,000 watts in 1 kilowatt. "Kilo" is the metric prefix for thousand, making the conversion straightforward.
Why is horsepower still used instead of watts?
Horsepower has historical significance in automotive markets, especially in the US. It's more relatable for consumers familiar with older vehicle specifications, though watts/kW are standard in modern engineering.