Power Converter
Convert between different units of power measurement including watts, horsepower, BTU/hour, kilowatts, and more. Essential for electrical, mechanical, and thermal power calculations.
Conversion Settings
No value entered
Conversion Result
Conversion result will appear here
Enter a value and click "Convert" to start
Common Power Conversions
💡 Power vs Energy
Power is the rate of energy transfer (energy per unit time).Energy is the total amount of work done. Power × Time = Energy. For example: 1 kW × 1 hour = 1 kWh of energy.
About Power Converter
A professional power converter that handles accurate conversions between electrical, mechanical, and thermal power units including watts, horsepower, BTU/hour, and kilowatts. This versatile tool supports both metric and imperial power measurements for comprehensive engineering and electrical applications.
Why use a Power Converter?
Critical for electrical engineers designing power systems, mechanical engineers specifying motors, and HVAC professionals calculating heating and cooling requirements. Ensures accurate power calculations for equipment selection, energy efficiency analysis, and system design to prevent undersizing or oversizing of components.
Who is it for?
Essential for electrical engineers, mechanical engineers, HVAC technicians, automotive professionals, and renewable energy specialists. Also valuable for students studying electrical or mechanical engineering, technicians working with motors and generators, and professionals involved in energy system design.
How to use the tool
Input your power value in the designated field
Select the source power unit from the comprehensive dropdown
Choose your target power unit for conversion
View the precise converted result with decimal accuracy
Use the converted power value for equipment specifications or calculations
Frequently Asked Questions
How do I convert power units?
Enter the source value, pick the 'from' and 'to' units, and the result appears instantly. Supports W, kW, MW, hp (mechanical), PS / hp (metric/DIN), BTU/h, ft·lbf/s. Copy the converted value to clipboard. Conversion runs entirely in your browser — values never leave the device. Decimal precision is configurable; default shows 4-6 significant figures, appropriate for most use cases. For scientific work needing more precision, increase the decimal places in the settings.
What power units does this converter support?
W, kW, MW, hp (mechanical), PS / hp (metric/DIN), BTU/h, ft·lbf/s. The set covers SI base and derived units, common imperial/US-customary units, and domain-specific units where relevant. SI prefixes (k, M, G, m, μ, n) apply where applicable. For any unit not in the list that you need converted, mention it via feedback — the unit set evolves based on user requests.
How accurate is the power conversion?
Conversions use exact internationally-defined factors where they exist — no rounding loss at the math level. Mechanical hp: 1 hp = 745.6998715822702 W (defined precisely). Metric hp: 1 PS = 735.49875 W. The difference comes from the original definitions (mechanical hp from James Watt's horse-pulling estimate; PS from a European standardization of the same concept). Output precision is bounded by the displayed decimal places (configurable, typically 4-6 by default). For extreme precision needs (scientific publications), increase the displayed decimals to match your significant-figure requirements.
What's the formula to convert horsepower to kilowatts?
kW = hp × 0.7457 (mechanical hp). Automotive specs comparison (US horsepower vs European PS), electric vs combustion engine comparisons (kW is unambiguous), HVAC sizing (BTU/h ↔ kW). For other power-unit pairs, the tool applies the appropriate exact conversion factor automatically — no manual formula needed. The conversion preserves precision to the displayed decimal places; choose precision to match your downstream use (engineering specs typically need 3-4 significant figures; scientific work may need more).
What's the key accuracy caveat for power conversion?
**Mechanical hp ≠ metric hp / PS** — a critical caveat for automotive specifications. Mechanical (or 'imperial') horsepower = 745.7 W. Metric horsepower = PS (Pferdestärke) = 735.5 W. The difference is ~1.4%. A car spec listing '300 PS' is NOT 300 mechanical hp — it's about 295.8 mechanical hp. European specs typically use PS; US specs use mechanical hp; modern specs increasingly use kW (the SI unit, unambiguous). When comparing engine outputs across regions, always normalize to kW first.
What's a common real-world use case for power conversion?
Automotive specs comparison (US horsepower vs European PS), electric vs combustion engine comparisons (kW is unambiguous), HVAC sizing (BTU/h ↔ kW).
What power units are commonly confused?
**hp (mechanical) vs PS (metric) vs kW** — 1 hp = 0.7457 kW; 1 PS = 0.7355 kW. **kW vs kWh** — kW is instantaneous power; kWh is energy over time (use [Energy Converter](/tools/energy-converter/)). **BTU/h** — heating/cooling capacity; 12,000 BTU/h ≈ 3.5 kW (one cooling 'ton').
How do I handle very large or very small power values?
Use SI prefixes for clean scaling: kilo (10³), mega (10⁶), giga (10⁹), milli (10⁻³), micro (10⁻⁶), nano (10⁻⁹). For values beyond standard prefixes, the tool displays results in scientific notation (e.g. 1.23e+15) for readability. Mechanical hp: 1 hp = 745.6998715822702 W (defined precisely). Metric hp: 1 PS = 735.49875 W. The difference comes from the original definitions (mechanical hp from James Watt's horse-pulling estimate; PS from a European standardization of the same concept). For data interchange to other tools, copy the raw value; for human readers, use the precision that matches the context.
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