Online Power Unit Converter
| # | Unit name | Symbol | Conversion result |
|---|
| Scenario | W | kW | hp | BTU/h |
|---|
About the Online Power Unit Converter
Tool Introduction
This tool supports real-time conversion between 18 common power units. Power is a physical quantity indicating how quickly work is done, i.e., work completed per unit time, with the watt (W) as the base unit in the International System of Units. Whether calibrating engine power (horsepower ↔ kilowatt), converting air conditioner cooling capacity (refrigeration ton ↔ kilowatt), calculating appliance energy consumption (watt ↔ BTU/h), or measuring renewable energy installed capacity (megawatt ↔ gigawatt), enter a value to get an accurate result immediately.
Metric/SI units
Watt (W) is the base unit of power in the International System of Units, 1 W = 1 J/s (1 joule of work per second). Common derived units: milliwatt (mW) = 10⁻³ W, kilowatt (kW) = 10³ W, megawatt (MW) = 10⁶ W, gigawatt (GW) = 10⁹ W. Household appliances are generally labeled in watts or kilowatts (such as an air conditioner at 1500W or a microwave at 1000W), while power plant installed capacity is usually expressed in megawatts or gigawatts (such as the Three Gorges Hydropower Station total installed capacity of 22.5 GW).
Mechanical/engineering units
Metric horsepower (PS): commonly used in Europe and China, 1 PS = 735.49875 W, derived from the definition "1 horse lifts a 75 kg object 1 meter per second". Imperial horsepower (hp): commonly used in the UK and US, 1 hp = 745.6998715823 W, derived from Watt's original definition of steam engine power. Foot-pound per second (ft·lb/s): 1 ft·lb/s ≈ 1.3558 W. Automobile engine power is usually marked in horsepower (PS or hp); 1 PS ≈ 0.986 hp, with a slight difference between them.
Electricity units
Volt-ampere (VA): a unit of apparent power, used in AC systems. When the power factor equals 1, 1 VA = 1 W; in practice, due to inductive/capacitive loads, active power is less than apparent power. Kilovolt-ampere (kVA): a common capacity unit for transformers, UPS power supplies, etc., 1 kVA = 1000 VA. Megavolt-ampere (MVA): a capacity unit for large electrical equipment, 1 MVA = 10⁶ VA.
Thermal units
Calorie per second (cal/s): 1 cal/s = 4.184 W. Kilocalorie per hour (kcal/h): 1 kcal/h ≈ 1.163 W, often used in nutrition and human metabolic rate calculations. British Thermal Unit per hour (BTU/h): a core parameter for air conditioning and heating equipment in North America, 1 BTU/h ≈ 0.293 W; for example, household air conditioner cooling capacity is often expressed as 12000 BTU/h (about 3.5 kW), also called "1 horsepower". Refrigeration ton (RT): a common unit in the refrigeration industry, 1 RT = 12000 BTU/h ≈ 3.517 kW, referring to the power required to freeze 1 short ton (2000 pounds) of water at 0°C into 0°C ice within 24 hours.
Other special units
Erg per second (erg/s): a CGS power unit, 1 erg/s = 10⁻⁷ W, common in astronomy and microphysics. The Sun's radiant power is about 3.828×10²⁶ W, i.e., 3.828×10³³ erg/s.
Privacy and Security
All conversion logic is performed locally in your browser; no values are uploaded to a server. You can use it with confidence, without worrying about data leaks.
Tips
1. After entering any value, all units are automatically converted in real time; 2. The power gauge at the top shows the current power's visual position within the 1 W - 1 MW range in real time (logarithmic scale); 3. Click the circular button in the middle to swap the source and target units with one click; 4. The common conversions section provides typical scenarios for one-click switching; 5. The "Common power reference points" table at the bottom lists typical scenarios from LED bulbs to nuclear power plants for quick comparison.