What is a power converter?
Convert power among watts, kilowatts, megawatts, mechanical horsepower, metric horsepower and BTUs per hour. It is designed for quick everyday and technical unit comparisons without requiring sign-up or server-side calculation.
How does this converter work?
The calculator converts the entered value through a common reference unit or an exact scale relationship, then converts that reference value to the selected target unit. Intermediate values are not rounded. This follows the general NIST approach of choosing an appropriate conversion factor, canceling units and rounding the final quantity rather than intermediate steps.
Which units are supported?
Watt, kilowatt, megawatt, mechanical horsepower, metric horsepower, BTU per hour and foot-pound-force per second.
Use the unit labels carefully when similar names can represent different systems. The selected units are always shown again in the result panel.
How do you use this power converter?
- Enter the numerical value you want to convert.
- Select the starting unit.
- Select the target unit, or use Swap Units to reverse them.
- Keep precision on Automatic or choose a significant-digit setting.
- Select Convert, then review the conversion relationship and result details.
Conversion example
1 mechanical horsepower is approximately 745.6998716 watts, while 1 metric horsepower is 735.49875 watts.
Accuracy, definitions and rounding
Horsepower has multiple definitions. Mechanical and metric horsepower are listed separately so they are not treated as interchangeable.
For important engineering, scientific, commercial or regulatory work, confirm that the unit definition, measurement uncertainty and required significant digits match the standards used in your application.
Power ratings, energy use and equipment comparisons
Power describes the rate at which energy is transferred or used. Watts and kilowatts are power units, while kilowatt-hours measure energy accumulated over time. Converting a motor or appliance rating from watts to kilowatts therefore does not calculate its electricity consumption; operating time and the real load are still needed for an energy estimate.
Horsepower ratings also need context. A machine may list electrical input power, mechanical output power, a nominal motor rating or a short peak value, and those labels are not automatically interchangeable even after the units are converted. When comparing equipment, use ratings measured on the same basis and follow the manufacturer documentation. Efficiency, startup demand and operating conditions can cause actual input to differ from a simple nameplate comparison. Preserve the source unit and a sensible number of significant digits so the converted figure does not imply more measurement precision than the original rating provides.
Frequently asked questions
Sources and methodology
The calculation relationships and explanatory notes are based on authoritative measurement references. Links open the original source so you can verify the unit definitions and conversion guidance.