About

Power conversion is a critical operation in systems engineering, requiring distinction between various historical and physical definitions of work rates. A discrepancy between Mechanical Horsepower (745.7 W) and Metric Horsepower (735.5 W) can lead to mechanical failure in high-tolerance motor specifications. Similarly, thermal engineering relies on precise translations between Watts and British Thermal Units (BTU) based on specific temperature standards (IT vs. Thermochemical).

This tool provides a rigorous conversion engine for over 80 distinct power units. It encompasses the full SI spectrum (Yoctowatt to Yottawatt), specialized HVAC units (Tons of Refrigeration), and logarithmic telecommunications units (dBm, dBW). Calculations utilize high-precision floating-point logic to ensure accuracy across magnitudes, from sub-atomic particle energy rates to galactic luminosity levels.

Formulas

Power P represents the derivative of work W with respect to time t. In linear conversion contexts, we define a conversion factor k relative to the base SI unit (Watt).

P_target = P_source × k_sourcek_target

For logarithmic units such as dBm (decibels relative to one milliwatt), the relationship is non-linear defined by:

P_dBm = 10 × log₁₀(1000 × P_W)

Reference Data

Unit Standard	Symbol	Definition (Watts)	Primary Application
SI Base	W	1.0	General Physics, Electrical
Mechanical HP	hp(I)	745.699872	US/UK Automotive
Metric HP	hp(M) / PS	735.49875	European Automotive
Electrical HP	hp(E)	746.0	Electric Motors
Boiler HP	hp(S)	9,809.5	Steam Generation
Refrigeration Ton	RT	3,516.853	HVAC Capacity
BTU (IT) / Hour	BTU/h	0.293071	Heating Systems
Poncelet	p	980.665	Historical French Engineering
Lusec	lusec	0.001333	Vacuum Technology
Decibel-milliwatt	dBm	Logarithmic	Radio/Fiber Optics

Frequently Asked Questions

They are derived from different physical constants. Mechanical Horsepower (Imperial) is defined as 550 foot-pounds per second (~745.7 Watts). Metric Horsepower (Pferdestärke) is defined as the force to lift 75 kilograms by 1 meter in 1 second (~735.5 Watts). In precision engineering, this 1.4% difference is significant.

Unlike linear units, dBm cannot be multiplied by a simple factor. It represents a power ratio in decibels referenced to one milliwatt. The tool uses the formula: P(dBm) = 10 · log10(1000 · P(W)).

By default, this tool uses the International Table (IT) definition of the British Thermal Unit, where 1 BTU ≈ 1,055.05585 Joules. Thermochemical and Mean BTU variants differ slightly and are generally used in specific scientific contexts.

Yes, units such as the Lusec (Litre-micron per second) and Clusec are included to support vacuum pump throughput calculations.