Power Converter

Welcome to the Power Converter, a comprehensive tool for converting between 10 different power units including Watts, Kilowatts, Megawatts, Gigawatts, mechanical and metric Horsepower, BTU per hour, Ton of Refrigeration, Foot-Pound per Second, and Calories per Second. Whether you are working on HVAC systems, automotive engineering, electrical installations, or physics calculations, this converter provides instant, accurate conversions with real-world context.

Understanding Power Units

Power is the rate at which energy is transferred or converted. It measures how quickly work is done. The SI unit of power is the Watt (W), named after Scottish engineer James Watt. Understanding different power units is essential for engineers, technicians, and anyone working with electrical systems, engines, or HVAC equipment.

SI Units: Watt Family

• Watt (W): The base SI unit of power. One Watt equals one Joule per second (1 W = 1 J/s). A typical LED light bulb uses 10-15 W.
• Kilowatt (kW): 1,000 Watts. Common for household appliances. A microwave uses about 1 kW.
• Megawatt (MW): 1,000,000 Watts. Used for power plants and large industrial equipment.
• Gigawatt (GW): 1,000,000,000 Watts. Used for measuring national power consumption and large power plants. As Doc Brown said, "1.21 gigawatts!"

Horsepower Variants

• Mechanical Horsepower (hp): Defined by James Watt as 550 ft·lb/s or 745.7 W. Used in the US and UK for engines.
• Metric Horsepower (PS): Also called "pferdestärke" in German or "cavalli vapore" in Italian. Equals 735.5 W. Used in Europe and Asia for automotive ratings.

Tip: When comparing car engines between US and European specifications, remember that a 100 PS engine is approximately 98.6 hp (mechanical).

HVAC and Thermal Units

• BTU per hour (BTU/h): British Thermal Unit per hour. Common in North America for heating and cooling systems. 1 BTU/h = 0.293 W. A window AC unit is typically 5,000-12,000 BTU/h.
• Ton of Refrigeration (TR): The cooling capacity to freeze one short ton (2,000 lbs) of ice in 24 hours. 1 TR = 3,516.85 W = 12,000 BTU/h. Home AC systems are typically 2-5 tons.

Other Power Units

• Foot-Pound per Second (ft·lb/s): Imperial unit of power. 1 ft·lb/s = 1.356 W. Related to horsepower: 550 ft·lb/s = 1 hp.
• Calorie per Second (cal/s): Thermal power unit. 1 cal/s = 4.184 W. Used in food science and thermal calculations.

Conversion Formulas

All conversions use the Watt as the base unit. To convert between any two units:

Quick Reference Factors

Common Conversion Examples

• 1 hp to kW: 1 × 745.7 ÷ 1000 = 0.7457 kW
• 1 kW to hp: 1 × 1000 ÷ 745.7 = 1.341 hp
• 1 TR to BTU/h: 1 × 3516.85 ÷ 0.293 = 12,000 BTU/h
• 100 hp to kW: 100 × 745.7 ÷ 1000 = 74.57 kW
• 5000 BTU/h to Watts: 5000 × 0.293 = 1,465 W

Real-World Power Examples

Frequently Asked Questions

What is the difference between mechanical and metric horsepower?

Mechanical horsepower (hp) equals 745.7 Watts and is used in the US and UK. Metric horsepower (PS or cv) equals 735.5 Watts and is used in Europe and Asia. The difference is about 1.4%, so 100 metric HP equals approximately 98.6 mechanical HP.

How many Watts are in a kilowatt?

There are exactly 1,000 Watts in 1 kilowatt. The prefix "kilo" means thousand, so 1 kW = 1,000 W. Similarly, 1 Megawatt (MW) = 1,000,000 W and 1 Gigawatt (GW) = 1,000,000,000 W.

What is a Ton of Refrigeration?

A Ton of Refrigeration (TR) is a unit of power used in HVAC systems, equal to 3,516.85 Watts or about 12,000 BTU/h. It represents the cooling capacity needed to freeze one short ton (2,000 lbs) of ice in 24 hours. A typical home AC unit is 2-5 tons.

What is BTU per hour used for?

BTU per hour (BTU/h) measures heating and cooling power in HVAC systems, particularly in North America. 1 BTU/h equals 0.293 Watts. Air conditioners, furnaces, and water heaters are commonly rated in BTU/h. A window AC unit might be 5,000-12,000 BTU/h.

How much power does a typical home use?

Average US household electricity consumption is about 30 kWh per day, which averages 1.25 kW continuously. Peak demand can reach 5-10 kW when multiple appliances run simultaneously. A 200-amp service provides about 48 kW maximum capacity.

Related Concepts

• Energy vs Power: Power is the rate of energy transfer. Energy = Power × Time. A 100 W light bulb running for 10 hours uses 1 kWh of energy.
• Torque vs Power: In engines, Power = Torque × Angular Velocity. More horsepower means faster acceleration; more torque means better pulling power.
• Electrical Power: P = V × I (Power = Voltage × Current) for DC circuits, or P = V × I × PF for AC circuits where PF is the power factor.

Additional Resources

• Watt - Wikipedia
• Horsepower - Wikipedia
• BTU - Wikipedia
• Ton of Refrigeration - Wikipedia