Power Converter
Convert between watts, kilowatts, megawatts, horsepower, BTU per hour, tons of refrigeration and every other unit of power.
1 watt = 0.001 kilowatts
Most used power units
- Watt W Base unit
- Kilowatt kW 1 kW = 1,000 W
- Horsepower hp 1 hp = 745.69987 W
- BTU per hour BTU/h 1 BTU/h = 0.29307107 W
- Megawatt MW 1 MW = 1,000,000 W
- Metric horsepower PS 1 PS = 735.49875 W
- Ton of refrigeration TR 1 TR = 3,516.8528 W
- Gigawatt GW 1 GW = 1,000,000,000 W
- Milliwatt mW 1 mW = 0.001 W
- Kilovolt-ampere kVA 1 kVA = 1,000 W
- Volt-ampere VA 1 VA = 1 W
- Kilocalorie per hour kcal/h 1 kcal/h = 1.1622222 W
Popular power conversions
- Kilowatts to horsepower 1 kW = 1.341022 hp
- Horsepower to kilowatts 1 hp = 0.7456999 kW
- Watts to kilowatts 1 W = 0.001 kW
- Kilowatts to watts 1 kW = 1,000 W
- BTUs per hour to watts 1 BTU/h = 0.2930711 W
- Watts to BTUs per hour 1 W = 3.412142 BTU/h
- BTUs per hour to tons of refrigeration 1 BTU/h = 0.00008333333 TR
- Tons of refrigeration to kilowatts 1 TR = 3.516853 kW
- Metric horsepower to kilowatts 1 PS = 0.7354987 kW
- Kilowatts to metric horsepower 1 kW = 1.359622 PS
- Horsepower to watts 1 hp = 745.6999 W
- Megawatts to kilowatts 1 MW = 1,000 kW
- Watts to horsepower 1 W = 0.001341022 hp
- Metric horsepower to horsepower 1 PS = 0.9863201 hp
- Kilowatts to BTUs per hour 1 kW = 3,412.142 BTU/h
- Kilocalories per hour to watts 1 kcal/h = 1.162222 W
What is power?
Power is the rate at which energy is used, produced or transferred: energy per unit of time. The SI unit is the watt, one joule per second, named after the Scottish engineer James Watt. A 60-watt bulb turns 60 joules of electrical energy into light and heat every second.
Engines and motors are still rated in horsepower, a unit James Watt himself defined to sell steam engines to mine owners who used horses. Air conditioners and heating systems in the US are rated in BTU per hour and tons of refrigeration.
Power and energy are easy to confuse. A kilowatt (kW) is a rate; a kilowatt-hour (kWh) is an amount of energy, one kilowatt used for one hour. For amounts of energy, see the energy converter.
Common power equivalents
- 1 kilowatt = 1,000 W ≈ 1.341 hp ≈ 3,412 BTU/h
- 1 horsepower (mechanical) ≈ 745.7 W; 1 metric horsepower (PS) ≈ 735.5 W
- 1 ton of refrigeration = 12,000 BTU/h ≈ 3.517 kW
- 1 BTU/h ≈ 0.2931 W
Power units from smallest to largest
Every proportional power unit on the site, ordered by size and expressed in watts.
- Picowatt 1 × 10-12 W
- Nanowatt 1 × 10-9 W
- Erg per second 1 × 10-7 W
- Microwatt 0.000001 W
- Milliwatt 0.001 W
- Foot-pound per minute 0.022597 W
- BTU per hour 0.293071 W
- Watt 1 W
- Volt-ampere 1 W
- Kilocalorie per hour 1.16222 W
- Foot-pound per second 1.35582 W
- Calorie per second 4.184 W
- Kilogram-force meter per second 9.80665 W
- BTU per minute 17.5843 W
- Human power (resting) 100 W
- Thousand BTU per hour 293.071 W
- Metric horsepower 735.499 W
- Hydraulic horsepower 745.7 W
- Horsepower 745.7 W
- Electrical horsepower 746 W
- Poncelet 980.665 W
- Kilowatt 1,000 W
- Kilovolt-ampere 1,000 W
- BTU per second 1,055.06 W
- Ton of refrigeration 3,516.85 W
- Japanese refrigeration ton 3,860 W
- Boiler horsepower 9,809.5 W
- Megawatt 1,000,000 W
- Gigawatt 1,000,000,000 W
- Terawatt 1,000,000,000,000 W
- Petawatt 1 × 1015 W
- Solar luminosity 3.828 × 1026 W
All 32 power units
Metric (SI)
Horsepower
Heat & refrigeration
- BTUs per hour
- BTUs per minute
- BTUs per second
- Calories per second
- Japanese refrigeration tons
- Kilocalories per hour
- Thousand BTU per hour
- Tons of refrigeration
Mechanical & other
Frequently asked questions
How many watts are in a horsepower?
A mechanical (imperial) horsepower is about 745.7 W; a metric horsepower (PS, CV) is about 735.5 W.
What is the difference between kW and kWh?
kW measures power (a rate); kWh measures energy (an amount). A 2 kW heater running for 3 hours uses 6 kWh.
How many BTU is a ton of air conditioning?
One ton of refrigeration is 12,000 BTU per hour, the cooling power of melting one short ton of ice in 24 hours.