Free Power Conversion Calculator
Convert power between watts, kilowatts, horsepower, BTU per hour and other units.
Your value is converted to watts using each unit's factor, then divided by the target unit's factor. All other units are listed together.
How to use the Power Conversion Calculator
- Enter your values, choosing the units you are working in.
- Read the result and the supporting numbers shown beneath it.
- Check the result against a second method or a reference table before you rely on it.
About the Power Conversion Calculator
Convert power between watts, kilowatts, horsepower, BTU per hour and other units.
Quick, reliable engineering arithmetic saves time on site and in the workshop. These tools show their working so you can check the result.
Getting started with the Power Conversion Calculator
Using the power conversion calculator takes a minute or two. Your entries are saved in this browser, so you can come back later and carry on.
Tips for better results
Mechanical horsepower (745.7 W) and metric horsepower (735.5 W) differ slightly, so pick the right one. BTU per hour is a rate, unlike plain BTU.
Keep units consistent from start to finish.
These tools are for estimates. Safety critical designs need a qualified engineer.
Privacy and where your data goes
Everything you type into the power conversion calculator stays on your own device. Zapxa does not receive your numbers or documents. If you clear your browser data, your saved entries will be removed, so download a PDF of anything you want to keep.
Frequently asked questions
How many watts are in a horsepower?
One mechanical horsepower is about 745.7 watts, and a metric horsepower is about 735.5 watts.
How many BTU per hour is a kilowatt?
One kilowatt is about 3,412 BTU per hour, as 1 BTU/h is about 0.293 W.
Is the power conversion calculator free?
Yes. It is free to use with no signup, no watermark and no usage limits.
Is my data private?
Yes. Your inputs are processed in your browser and saved only in its local storage. They are not uploaded to our servers.
Does it work on mobile?
Yes. Zapxa works on phones, tablets and desktops. Use the print button or download a PDF to keep a copy.
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