Power Unit Conversion

Enter a value in any unit below to instantly convert between watt, kilowatt, horsepower (imperial/metric), BTU/h, BTU/s, kilocalorie/h, kilocalorie/s, kgf-m/s, lbf-ft/s.

Watt (W)

W

Kilowatt (kW)

kW

Imperial Horsepower (HP)

HP

Metric Horsepower (PS)

PS

Kilocalorie per hour (kcal/h)

kcal/h

Kilocalorie per second (kcal/s)

kcal/s

BTU per hour (BTU/h)

BTU/h

BTU per second (BTU/s)

BTU/s

Kilogram-force meter per second (kgf·m/s)

kgf·m/s

Pound-force feet per second (lbf·ft/s)

lbf·ft/s

Unit Conversion Relations

1 kilowatt = 1.34 imperial horsepower = 1.36 metric horsepower
1 kilowatt = 860 kilocalories per hour = 0.24 kilocalories per second
1 kilowatt = 3412 BTU per hour = 0.95 BTU per second
1 kilowatt = 102 kilogram-force-meter per second = 738 pound-force-feet per second

FAQ

What is the difference between power and energy?
Power is the rate of energy transfer or conversion, measured in watts (W). Energy is the capacity to do work, measured in joules (J) or kilowatt-hours (kWh). Power = Energy ÷ Time. For example, a 100W light bulb uses 100J of energy per second.
Why are there different types of horsepower?
Imperial horsepower (HP) = 745.7 watts, based on James Watt's definition. Metric horsepower (PS) = 735.5 watts, based on metric units. The difference is about 1.4%. Always specify which type when dealing with international equipment specifications.
How do I convert between mechanical and thermal power units?
Use these key conversions: 1 kW = 3412 BTU/hr = 860 kcal/hr. For example, a 5 kW heater produces 5 × 3412 = 17,060 BTU/hr of heat. The calculator handles these conversions automatically using established thermodynamic relationships.
What are typical power values for common applications?
LED bulb: 10-20W, laptop: 50-100W, microwave: 1000W, car engine: 100-500 HP (75-375 kW), industrial motor: 1-1000 kW, power plant: 100-1000 MW. These ranges help understand the scale of power requirements in different applications.
How accurate are power unit conversions?
The conversions use internationally defined standards. For example, 1 HP = exactly 745.699872 W by definition. The calculator maintains precision suitable for engineering calculations, motor sizing, and energy efficiency analysis.
What are common applications for power calculations?
Power calculations are essential in electrical engineering (load analysis), mechanical engineering (motor sizing), HVAC design (heating/cooling loads), automotive (engine power), and energy management (consumption analysis). They help determine equipment requirements and operating costs.