How to Use This Tool
Enter a Value
Type the power value you want to convert into the input field. Decimals and scientific notation are supported.
Choose Your Units
Pick a From unit and a To unit from the dropdowns. Use the swap button to flip them instantly.
Read the Result
The converted value appears instantly below the inputs. Click Copy to put it on your clipboard.
See All Conversions
Scroll down to see the same power converted into every other supported unit at once.
Frequently Asked Questions
Is this tool really free?
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Yes, completely free with no limits and no sign-up. Everything runs in your browser with no server costs.
Is my data sent to a server?
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No. All conversion math happens directly in your browser. Nothing you type is ever sent anywhere.
What units are supported?
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11 units: Watt, Kilowatt, Megawatt, Gigawatt, Milliwatt, Horsepower (mechanical), Horsepower (metric), BTU per hour, Calories per second, Foot-pounds per second, and Ton of Refrigeration.
What is the difference between mechanical and metric horsepower?
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Mechanical horsepower (hp) is about 745.7 watts, used mainly in the US and UK. Metric horsepower (PS) is about 735.5 watts, used in most of Europe and Asia. They are close but not identical.
What is a Ton of Refrigeration?
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A ton of refrigeration is the cooling power needed to melt one ton of ice in 24 hours, equal to about 3,517 watts. It is used to rate air conditioning and refrigeration systems.
What is BTU per hour?
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BTU per hour measures the rate of energy transfer. It is commonly used to rate heating systems, air conditioners, and gas appliances in the United States.
How do I convert horsepower to watts?
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Set From to Horsepower (mechanical) and To to Watt. One mechanical horsepower is about 745.7 watts. One metric horsepower is about 735.5 watts.
How accurate are the conversions?
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The tool uses standard conversion factors and displays up to 10 significant figures. Results are accurate for everyday, educational, and professional use.
Can I see all conversions at once?
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Yes. Below the main result, the tool shows the same value converted into every other unit in a scrollable list.
Does it support decimals?
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Yes. You can type values like 0.5, 1.5, or 7.46e2. The tool handles all standard number formats.
What Is Power Converter?
Power Converter is a free tool that converts between 11 power units right in your browser. It covers the watt family (milliwatt to gigawatt), both mechanical and metric horsepower, heating and cooling units (BTU per hour, ton of refrigeration), and traditional units (calories per second, foot-pounds per second). Nothing you type is ever sent anywhere - all math runs locally on your device.
The result updates live as you type, and a full conversion table shows the same value in every other unit at once. Use the swap button to flip your units instantly, or copy the result to your clipboard in one click.
Features Explained
11 Power Units
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Convert between Watt, Kilowatt, Megawatt, Gigawatt, Milliwatt, Horsepower (mechanical), Horsepower (metric), BTU/hour, Calories/second, Foot-pounds/second, and Ton of Refrigeration.
Watt Family
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From milliwatt (tiny electronics) through watt and kilowatt (household appliances) up to megawatt and gigawatt (power plants and grids).
Two Types of Horsepower
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Mechanical horsepower (745.7 W, used in the US and UK) and metric horsepower (735.5 W, used in Europe and Asia). The tool includes both so you always pick the right one.
Heating and Cooling Units
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BTU per hour for furnaces and heaters. Ton of Refrigeration for air conditioning systems. Convert them to watts or kilowatts to compare across systems.
Traditional Units
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Calories per second and foot-pounds per second for physics, engineering, and legacy specifications.
Instant Conversion
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The result updates live as you type. There is no Convert button to click - you see the answer the moment your input changes.
All Conversions at Once
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Below the main result, a scrollable table shows the same power converted into every other unit simultaneously.
Swap Button
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Click the swap button between the From and To dropdowns to flip them instantly. The result recalculates right away.
Copy to Clipboard
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Click Copy to put the converted value on your clipboard instantly, ready to paste into a document, spec sheet, or message.
100% Browser-Based
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All conversion math runs directly in your browser. Nothing you type is ever sent to any server - complete privacy.
Who Is This Tool For?
Electrical Engineers
Convert between watts, kilowatts, and megawatts for circuit design, load calculations, and power system specifications.
Mechanical Engineers
Convert between horsepower, watts, and foot-pounds per second for motor sizing, drivetrain design, and performance calculations.
Automotive Enthusiasts
Convert engine power between mechanical horsepower, metric horsepower, and kilowatts when comparing cars from different regions.
HVAC Technicians
Convert between BTU per hour, tons of refrigeration, and kilowatts when sizing and comparing heating and cooling systems.
Electricians
Convert between watts and kilowatts when sizing breakers, wiring, and electrical panels for residential and commercial jobs.
Solar Panel Owners
Convert solar panel and inverter ratings between watts, kilowatts, and horsepower to understand your system's output.
Students
Convert between watts, horsepower, and BTU per hour for physics and engineering homework and lab reports.
Teachers
Demonstrate power conversions in real time during lessons and help students understand the relationships between units.
Homeowners
Convert appliance power ratings between watts and kilowatts to understand energy consumption and compare products.
Generator Buyers
Convert generator ratings between watts, kilowatts, and horsepower to choose the right size for your needs.
Boaters
Convert outboard and inboard motor power between horsepower and kilowatts when comparing engines from different manufacturers.
Cyclists
Convert cycling power output between watts and horsepower for performance tracking and training analysis.
Motorsport Fans
Convert race car and motorcycle power between mechanical HP, metric HP, and kilowatts for cross-regional comparisons.
Industrial Workers
Convert motor and machinery ratings between kilowatts and horsepower for equipment selection and maintenance.
Renewable Energy Workers
Convert wind turbine and solar farm output between megawatts, kilowatts, and gigawatts for project planning.
Data Center Managers
Convert server rack and cooling power between kilowatts, BTU per hour, and tons of refrigeration for capacity planning.
Fitness Enthusiasts
Convert exercise machine power output between watts and horsepower to understand your effort level.
Audio Engineers
Convert amplifier power ratings between watts and milliwatts when sizing speakers and headphone amplifiers.
Pilots
Convert aircraft engine power between horsepower, kilowatts, and shaft horsepower for performance calculations.
Farmers
Convert tractor and equipment power between horsepower and kilowatts when comparing machines from different countries.
Researchers
Convert between SI and traditional power units for cross-referencing data across different fields and publications.
Journalists
Convert power figures in stories about energy, vehicles, and infrastructure so readers in different regions understand.
Real Estate Agents
Convert HVAC system ratings between BTU per hour and kilowatts for property energy efficiency comparisons.
Anyone
Quickly convert any power value for any reason - appliances, vehicles, science, fitness, or curiosity.
Tips for Best Results
Mechanical vs metric horsepower
Mechanical HP (745.7 W) is used in the US, UK, and Japan. Metric HP or PS (735.5 W) is used in most of Europe and Asia. Pick the right one for your region.
Quick HP to kW estimate
Divide horsepower by 1.34 for a rough kilowatt estimate. For example, 200 HP is roughly 149 kW (exact is 149.14 kW).
BTU per hour for HVAC
Furnaces and air conditioners are rated in BTU/h. A 12,000 BTU/h unit equals 1 ton of refrigeration or about 3.5 kW of cooling.
Gigawatt for power plants
Large power plants produce in the gigawatt range. 1 GW = 1,000 MW = 1,000,000 kW. A typical nuclear plant produces about 1 GW.
Milliwatt for electronics
Tiny electronic components, sensors, and hearing aids operate in the milliwatt range. 1 W = 1,000 mW.
Use the All Conversions table
Scroll below the main result to see the same power in every other unit at once. Great for comparing across scales.
Use the swap button
Click the swap button between the dropdowns to flip From and To instantly.
Copy the result in one click
Click Copy next to the result to put the value on your clipboard, ready to paste into a spec sheet, report, or message.
Scientific notation for extremes
For very large or very small values, type scientific notation like 1.21e9 (1.21 gigawatts) instead of counting zeros.
Privacy is built in
Nothing you type is ever sent to any server. All math runs in your browser, so your data stays completely private.
Privacy & Security
This tool runs 100% in your browser. Your files stay entirely on your own device. Nothing is uploaded, nothing is shared, and no server, advertiser, or third party has access to your files.
If a tool saves your work on your own device, you can remove it at any time using the Clear All button. Some tools rely on an external service to return their result; in those cases, only the minimum data required for the request is sent, and never your files or content. Any ads shown on this page run in an isolated frame and cannot read, touch, or transmit anything you upload, paste, type, or download here. Advertisers may see standard visit information like your IP address and which page you're on, as described in our Privacy Policy, but your data itself stays fully under your control.
