Free Power Converter – Convert Watts, kW & Horsepower
Convert between watts, kilowatts, horsepower and BTU/hour.
About the Power Converter
What is the Power Converter?
A power converter changes a power rating between watts, kilowatts, mechanical and metric horsepower, and thermal units.
Why use this calculator?
Engine specs, appliance labels and HVAC equipment use different power units, so conversion keeps comparisons fair.
How to use it
- Enter the power value.
- Choose the source and target units.
- Read the converted power.
Formula
One mechanical horsepower equals about 745.7 watts.
Metric horsepower (PS) is defined as 735.49875 watts, slightly less than mechanical horsepower.
Frequently Asked Questions
How many watts is one horsepower?
One mechanical horsepower is about 745.7 watts.
What is the difference between horsepower and metric horsepower?
Metric horsepower (Pferdestärke, PS) is about 735.5 W, slightly smaller than the 745.7 W mechanical horsepower.
How precise are the conversions?
Conversions use standard, internationally defined factors and are rounded for display. They are accurate to the number of digits shown.
Can I convert back and forth without losing accuracy?
Yes. Enter the original value to get an exact inverse conversion; avoid chaining rounded results if you need maximum precision.
Which measurement system is used?
Both metric (SI) and US customary / imperial units are supported and clearly labelled.
Is this calculator free to use?
Yes. Every calculator on this site is completely free, with no hidden fees, no subscriptions and no limits on how many times you can use it.
How accurate are the results?
We use standard, widely accepted formulas and calculate in your browser using double-precision arithmetic. Results are rounded for readability, so treat them as reliable estimates rather than a guarantee. Real-world factors can vary the true figure.
Can I add this calculator to my own website?
Yes. Open this calculator page and use the "Add to your website" box in the sidebar to copy a ready-made iframe snippet, then paste it into any HTML page.
Does it work on a phone or tablet?
Yes. The layout is fully responsive, so it works on desktops, laptops, tablets and mobile phones, and every input adapts to touch screens.
Is the information I type kept private?
Yes. All calculations run locally in your browser. Nothing you enter is uploaded, stored or shared with anyone.