Converter category
Power Converter
Convert between watts, kilowatts, megawatts, horsepower (mechanical, metric, electrical, boiler), BTU/hour, tons of refrigeration, and many other power units.
Universal Power Converter
About power conversions
Power conversions are used in electrical engineering, automotive performance, heating and cooling, fitness equipment, and energy management. Our power converter covers SI units such as watts, kilowatts, and megawatts, plus electrical units like volt-amperes and kilovolt-amperes. It includes mechanical units such as horsepower, metric horsepower, boiler horsepower, and foot-pounds per minute, plus thermal units like BTU per hour, BTU per second, and kilocalories per hour. Whether you are sizing an engine, comparing appliance ratings, or analyzing energy consumption, this converter gives accurate results.
Most popular power conversions
Available units
Popular power conversions (2162 total)
Unit definitions
Watt (W)
A watt is the SI unit of power, the rate of energy transfer. 1 W = 1 J/s.
Origin: Named after James Watt, inventor of practical steam engine.
Current use: Electrical rating, Light bulbs, Appliance specs
Kilowatt (kW)
A kilowatt is 1000 watts, commonly used for motor and appliance ratings.
Origin: Standard unit for most electrical devices.
Current use: Motor vehicles, Home appliances, Industrial machinery
Megawatt (MW)
A megawatt is one million watts, used for large facilities and power plants.
Origin: Large-scale power measurement unit.
Current use: Power plants, Data centers, Industrial processes
Horsepower (Mechanical) (hp)
Mechanical horsepower is 550 foot-pounds per second, about 746 W.
Origin: James Watt coined horsepower to market steam engines.
Current use: Engine rating, Vehicle power, Machinery
Horsepower (Metric) (PS)
Metric horsepower is slightly different from mechanical HP. 1 PS = 735.5 W.
Origin: Used in Germany and France for vehicle rating.
Current use: European vehicles, German engineering, Motorcycles
Electrical Horsepower (ehp)
Electrical horsepower is 746 watts, used for motor ratings in US.
Origin: Defined for electrical motors.
Current use: Electric motors, US industry, Motor specifications
Boiler Horsepower (boiler hp)
Boiler horsepower is the energy to evaporate 34.5 lb of water/hour at 212°F.
Origin: Original definition for steam boilers.
Current use: Boilers, Steam engines, Heating systems
BTU per Hour (BTU/h)
BTU per hour is the standard unit for HVAC cooling capacity. 1 RT ≈ 12,000 BTU/h.
Origin: Used for air conditioning and heating equipment rating.
Current use: HVAC systems, Air conditioners, Furnaces
Ton of Refrigeration (TR)
Ton of refrigeration is the heat to melt 1 ton of ice in 24 hours. 1 TR = 12,000 BTU/h.
Origin: Original refrigeration unit based on ice melting.
Current use: Refrigeration, HVAC, Cold storage
Foot-pound per Minute (ft·lb/min)
Power unit in Imperial system. 1 ft·lb/min = 0.0226 W.
Origin: Imperial unit of mechanical power.
Current use: Mechanical power, Historical engineering, Small power
Exawatt (EW)
1 quintillion watts. Total Sun's power output.
Origin: Metric prefix exa- = 10^18.
Current use: Solar constant, Astrophysics, Planetary
Petawatt (PW)
Quadrillion watts. Laser power.
Origin: Metric prefix peta- = 10^15.
Current use: Lasers, Research, Pulse power
Terawatt (TW)
Trillion watts. World power consumption.
Origin: Metric prefix tera- = 10^12.
Current use: World energy, Large grid, Geophysical
Hectowatt (hW)
100 watts. Bright light bulb.
Origin: Metric prefix hecto- = 100.
Current use: Lighting, Small appliances, Labs
Decawatt (daW)
10 watts. Small device.
Origin: Metric prefix deca- = 10.
Current use: Electronics, Small equipment
Deciwatt (dW)
0.1 watt. Very small.
Origin: Metric prefix deci- = 0.1.
Current use: RF power, Small electronics
Centiwatt (cW)
0.01 watt. Tiny power.
Origin: Metric prefix centi- = 0.01.
Current use: Low-power electronics, Research
Milliwatt (mW)
0.001 watt. Small electronics.
Origin: Metric prefix milli- = 0.001.
Current use: Electronics, Lasers, RF
Microwatt (µW)
One millionth of a watt.
Origin: Metric prefix micro- = 10^-6.
Current use: Pacemakers, Sensors, Medical
Nanowatt (nW)
One billionth of a watt.
Origin: Metric prefix nano- = 10^-9.
Current use: Radio receivers, Scientific
Picowatt (pW)
One trillionth of a watt.
Origin: Metric prefix pico- = 10^-12.
Current use: Nanotechnology, Research
Femtowatt (fW)
One quadrillionth of a watt.
Origin: Metric prefix femto- = 10^-15.
Current use: Advanced research, Spectroscopy
Attowatt (aW)
One quintillionth of a watt.
Origin: Metric prefix atto- = 10^-18.
Current use: Quantum optics, Fundamental physics
Horsepower (550 ft·lbf/s) (hp)
550 ft·lbf/s = 746 W. US mechanical hp.
Origin: James Watt's definition.
Current use: US engines, Machinery, Vehicles
Horsepower (Electric) (hp_E)
Electric motor hp = 746 W.
Origin: US electrical standard.
Current use: Electric motors, US industry
Horsepower (Water) (hp_W)
Water pump hp = 746.043 W.
Origin: Hydraulic standard.
Current use: Water pumps, Hydraulics
Pferdestaerke (PS) (PS)
German metric hp = 735.5 W.
Origin: German engineering.
Current use: European cars, German machinery
BTU (IT) per Minute (BTU/min)
17.6 watts. HVAC rate.
Origin: Cooling capacity.
Current use: Air conditioning, HVAC
BTU (IT) per Second (BTU/s)
1055 W. Large heating rate.
Origin: Heat transfer.
Current use: Industrial heating, Power
BTU (Th) per Hour (BTU_th/h)
0.293 watts. Small heat rate.
Origin: Thermodynamics.
Current use: Small heating, Labs
BTU (Th) per Minute (BTU_th/min)
17.6 watts. Heat transfer.
Origin: Thermodynamics.
Current use: HVAC, Heating
BTU (Th) per Second (BTU_th/s)
1054 W. Large heat rate.
Origin: Thermodynamics.
Current use: Industrial, Power
MBTU per Hour (MBTU/h)
293 watts. HVAC.
Origin: US heating standard.
Current use: US HVAC, Gas furnaces
MBH (MBH)
Same as MBTU/h. US HVAC.
Origin: US industry.
Current use: US heating, HVAC
Kilocalorie (IT) per Hour (kcal_IT/h)
1.16 watts. Metabolic rate.
Origin: Biology standard.
Current use: Metabolism, Nutrition, Biology
Kilocalorie (IT) per Minute (kcal_IT/min)
69.8 watts. Exercise power.
Origin: Biology.
Current use: Exercise physiology, Sports
Kilocalorie (IT) per Second (kcal_IT/s)
4187 watts. Large heat rate.
Origin: Thermodynamics.
Current use: Industrial heating, Power
Calorie (IT) per Hour (cal_IT/h)
Very small heat rate.
Origin: Small scale.
Current use: Labs, Small systems
Calorie (IT) per Minute (cal_IT/min)
Small heat rate.
Origin: Small scale.
Current use: Small heating, Labs
Calorie (IT) per Second (cal_IT/s)
4.2 watts. Moderate.
Origin: Heat transfer.
Current use: Food science, Labs
Foot-pound per Hour (ft·lbf/h)
Very small mechanical power.
Origin: Small scale.
Current use: Small mechanisms
Foot-pound per Minute (ft·lbf/min)
Small Imperial power.
Origin: US small scale.
Current use: Small motors, Labs
Erg per Second (erg/s)
CGS power = 0.1 µW.
Origin: CGS system.
Current use: Physics, Small systems
Kilovolt-Ampere (kVA)
Apparent power = 1000 VA.
Origin: Electrical engineering.
Current use: Generators, Transformers, UPS
Volt-Ampere (VA)
Apparent power unit.
Origin: Electrical standard.
Current use: Electrical, Power systems
Newton Meter per Second (N·m/s)
Same as watt. SI power.
Origin: Mechanics power.
Current use: Physics, Mechanics
Joule per Second (J/s)
Same as watt. SI.
Origin: Energy rate.
Current use: Physics, Engineering
Common uses for power conversions
Power conversions are used for appliance ratings, engine specifications, electricity bills, solar systems, HVAC sizing, motors, and fitness equipment.
Frequently asked questions about power
How many watts are in 1 horsepower?+
One mechanical horsepower equals approximately 745.7 watts.
What is the difference between kilowatt and kilowatt-hour?+
A kilowatt measures power, which is the rate of energy use. A kilowatt-hour measures energy used over time, equal to one kilowatt running for one hour.
Which power units does this converter support?+
It supports SI, electrical, mechanical, thermal, and imperial power units — over 45 in total.