About power units
Power is the rate at which work is done or energy is transferred. In engineering and everyday contexts you will commonly see power expressed in watts (W), kilowatts (kW) and horsepower (HP). The watt is the SI unit of power and is defined as one joule per second. A kilowatt is 1,000 watts and is commonly used for electrical power ratings (home appliances, motors).
Horsepower (HP)
Horsepower is a historically popular unit for engine power. There are several definitions of horsepower; this converter uses mechanical (imperial) horsepower where 1 hp ≈ 745.699872 W. Horsepower values are still commonly used in automotive specifications and some industrial equipment ratings.
Practical examples
- 1 hp ≈ 745.7 W — useful to convert small engine ratings to watts for electrical comparisons.
- 4 kW (4000 W) is roughly equivalent to 5.36 hp.
- When sizing backup generators or comparing motor outputs, convert everything to watts or kilowatts first for accurate summation.
How this tool works
This converter performs straightforward unit conversions client-side — no data leaves your browser. It converts any input value to watts as an intermediate step, then converts from watts to the target unit. Results are formatted with sensible precision: larger numbers are shown with two decimals and thousands separators, moderate numbers with three decimals, and small fractional values with sufficient significant figures.
Notes & tips
- If you need another horsepower definition (metric/SAE), convert to watts then apply the alternative factor manually — contact us if you want the converter extended.
- For aggregate power (multiple devices), convert each value to watts, sum them, then convert back to your preferred unit.
- This tool is best used for quick estimates and planning; for safety-critical engineering calculations consult manufacturer data and standards.
Tip: press Enter while focused on any input to trigger conversion. You can also use the right-side menu to jump to other converters.