Power converter
Convert watts, kilowatts, and megawatts to and from horsepower and BTU per hour, instantly and entirely in your browser. Nothing is uploaded.
The amount to convert. Leave empty or non-numeric for no result.
Metric and imperial power, side by side
Power is measured in the metric watt and its multiples (kilowatt, megawatt) alongside the mechanical horsepower still quoted for engines and BTU per hour used in heating and cooling. Mechanical horsepower is defined as 745.6998715822702 watts, so this converter steps between the families using that exact factor rather than a remembered 746. Pick any two units and convert in either direction.
Runs entirely on your device
There is no server, no account, and no upload. The math is a few lines of JavaScript that execute in your browser, so the tool works offline and your figures stay private, whether you are sizing a motor, an appliance, or an air conditioner.
Frequently asked questions
- Does this send my data anywhere?
- No. The converter is plain JavaScript that runs entirely in your browser. There is no upload, no network request, and no account. The numbers you type never leave your device.
- How many watts are in one horsepower?
- About 745.7. This converter uses mechanical (imperial) horsepower, defined as 745.6998715822702 watts, so 1 hp converts to that exact figure rather than a rounded 746 W.
- How many watts are in a kilowatt?
- Exactly 1000. A kilowatt is 1000 watts and a megawatt is 1,000,000 watts, so 1 MW = 1000 kW. These metric steps are exact powers of ten.
- Which units are supported?
- Watts, kilowatts, and megawatts, plus mechanical horsepower and BTU per hour. You can convert between any two in either direction.
- How precise are the results?
- Metric steps (W, kW, MW) are exact powers of ten, and horsepower and BTU per hour use standard conversion factors, so results are exact within floating-point limits. Long fractional results are rounded to twelve significant figures for readability.