Power Converter

How to Convert Power?

To convert power between different units, use the appropriate conversion factors. For example, to convert Watts to Kilowatts, divide by 1,000. To convert Horsepower to Watts, multiply by 745.7. This converter handles all common power units including SI units (W, kW, MW, GW) and practical units (hp, BTU/h, etc.).

Power Conversion Principles

1. Watt (W)

The Watt is the SI unit of power, defined as one joule per second. It is named after James Watt and is the most fundamental unit for measuring power. Power represents the rate at which energy is transferred or converted.

2. SI Multiples

Power units use standard SI prefixes: Kilowatt (kW) = 1,000 W, Megawatt (MW) = 1,000,000 W, Gigawatt (GW) = 1,000,000,000 W. These are commonly used in electrical systems, power plants, and energy consumption measurements.

3. SI Submultiples

For small power levels: Milliwatt (mW) = 0.001 W. These are used in electronics, radio transmitters, and low-power devices.

4. Horsepower

Horsepower is a traditional unit of power commonly used for engines and motors. There are three main types: Mechanical horsepower (hp) = 745.7 W, Metric horsepower (PS) = 735.5 W, and Electric horsepower (hp(E)) = 746 W.

5. British Thermal Unit

BTU (British Thermal Unit) per hour or per second is used in heating, cooling, and air conditioning systems. 1 BTU/h = 0.293 W, and 1 BTU/s = 1,055.06 W.

6. Mechanical Power Units

Foot-pound force per second (ft·lbf/s) and related units are used in mechanical engineering. 1 ft·lbf/s = 1.356 W.

7. Energy Rate Units

Joules per second (J/s) is equivalent to Watts. Kilocalories per hour (kcal/h) is used in nutrition and metabolism: 1 kcal/h = 1.163 W.

8. Conversion Formulas

• W to kW: W ÷ 1,000 = kW
• kW to MW: kW ÷ 1,000 = MW
• MW to GW: MW ÷ 1,000 = GW
• W to mW: W × 1,000 = mW
• hp to W: hp × 745.7 = W
• W to hp: W ÷ 745.7 = hp
• BTU/h to W: BTU/h × 0.293 = W
• W to BTU/h: W ÷ 0.293 = BTU/h

9. Refrigeration Ton

A ton of refrigeration (TR) is a unit of power used in air conditioning and refrigeration. 1 TR = 3,516.85 W, representing the heat extraction rate needed to freeze one short ton of water in 24 hours.

10. Common Applications

• Light bulbs: 5-100 W
• Laptop computers: 30-90 W
• Microwave ovens: 600-1,200 W
• Hair dryers: 1,000-1,800 W
• Electric vehicles: 50-200 kW
• Car engines: 50-500 hp (37-373 kW)
• Wind turbines: 1-5 MW
• Power plants: 500-2,000 MW
• Air conditioners: 1-5 TR (3.5-17.6 kW)

Common Power Units

Watt (W)

The SI unit of power, representing one joule per second. Used as the base unit for all power measurements in the International System of Units.

Kilowatt (kW), Megawatt (MW), Gigawatt (GW)

SI multiples of Watt used for higher power levels. Common in electrical systems, appliances, industrial equipment, and power generation.

Milliwatt (mW)

SI submultiple used for small power levels in electronics, laser pointers, and radio frequency applications.

Horsepower (hp)

Traditional unit for engines and motors. Three types exist: mechanical (745.7 W), metric/PS (735.5 W), and electric (746 W).

BTU per Hour and BTU per Second

Used in HVAC (heating, ventilation, and air conditioning) systems to measure heating and cooling capacity.

Foot-pound force per Second

Used in mechanical engineering to measure power output of engines and machinery.

Joule per Second (J/s)

Equivalent to Watt. Shows the direct relationship between power and energy transfer rate.

Kilocalorie per Hour (kcal/h)

Used in nutrition, metabolism studies, and some heating applications. Relates energy consumption to power.

Ton of Refrigeration (TR)

Standard unit in air conditioning and refrigeration industry. Represents the cooling power needed to freeze one ton of water in 24 hours.

Volt-ampere (VA) and Kilovolt-ampere (kVA)

Used in electrical engineering for apparent power in AC circuits. When power factor is 1, VA equals Watts.