Power Conversion
Convert power units like watts, kilowatts, megawatts, horsepower, BTU/h, and ft-lb/s with this free online power conversion calculator. Instant results with comparison chart.
About This Calculator
The Power Conversion Calculator is a free online tool that lets you convert between six popular power units instantly: watts (W), kilowatts (kW), megawatts (MW), mechanical horsepower (hp), British thermal units per hour (BTU/h), and foot-pounds per second (ft-lb/s). Simply enter a numeric value, select your source and target units, and click Convert to get the precise equivalent.
Power conversion uses standard scientific factors. One watt equals one joule per second, making it the SI base unit of power. One mechanical horsepower equals approximately 745.7 watts, a value defined by James Watt in the 18th century. One BTU/h equals about 0.293071 watts, commonly used for heating and cooling equipment ratings. The calculator also shows a comparison bar chart displaying your input value across all supported units side by side.
This tool is useful for engineers, electricians, HVAC technicians, automotive enthusiasts, students, and anyone who needs to convert power ratings between different unit systems. Whether you are comparing engine horsepower to electric motor kilowatts or sizing an air conditioner's BTU rating in watts, the converter handles it all.
Regional Notes
India: Power ratings are commonly expressed in kilowatts (kW) for electrical appliances and horsepower (hp) for vehicles and pumps. Electricity bills use kilowatt-hours (kWh) for energy consumption.
United States: Horsepower is widely used for engines (cars, lawn mowers, power tools), while BTU/h is standard for HVAC systems. Electrical power is typically listed in watts or kilowatts.
United Kingdom: Both metric (kW) and imperial (hp, BTU/h) units are in common use. Vehicle power is often advertised in both bhp (brake horsepower) and kW.
Common Power Conversion Formulas
- 1 kW = 1000 W
- 1 MW = 1,000,000 W
- 1 hp (mechanical) = 745.7 W
- 1 BTU/h = 0.293071 W
- 1 ft-lb/s = 1.35582 W
Frequently Asked Questions
How do I use the Power Conversion Calculator?
Enter a numeric value, select the source unit (From) and target unit (To), then click Convert. The calculator displays the result instantly along with a comparison chart showing the value in all supported power units.
What power units are supported?
The converter supports watts (W), kilowatts (kW), megawatts (MW), mechanical horsepower (hp), British thermal units per hour (BTU/h), and foot-pounds per second (ft-lb/s). All conversions use standard scientific conversion factors.
How do you convert horsepower to watts?
One mechanical horsepower equals approximately 745.7 watts. To convert hp to W, multiply the horsepower value by 745.7. For example, 10 hp × 745.7 = 7,457 W or 7.457 kW.
How do you convert BTU/h to watts?
One BTU per hour equals approximately 0.293071 watts. To convert BTU/h to W, multiply the BTU/h value by 0.293071. For example, a 10,000 BTU/h air conditioner produces about 2,931 watts of cooling power.
What is the difference between kW and kWh?
A kilowatt (kW) measures power, the rate of energy consumption at a given instant. A kilowatt-hour (kWh) measures energy, the total amount consumed over time. If a 1 kW appliance runs for 1 hour, it uses 1 kWh of energy.
Is this power conversion tool free?
Yes, all calculators on Calculy are completely free to use with no registration or limits. You can convert unlimited power units online.
How accurate are the power conversion results?
All conversions use scientifically accepted standard conversion factors: 1 hp = 745.7 W, 1 BTU/h = 0.293071 W, 1 kW = 1000 W, and 1 MW = 1,000,000 W for maximum precision.
Can I share a specific power conversion result?
Yes, the calculator saves your input values in the URL, so you can copy the page URL to share or bookmark any specific conversion result with all parameters preserved.