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Power Converter

Convert watts, kilowatts, horsepower, and BTU per hour in one place.

Decimal places4
Results
  • Milliwatt
    mW
  • Watt
    W
  • Kilowatt
    kW
  • Megawatt
    MW
  • Gigawatt
    GW
  • Horsepower (mechanical)
    hp
  • Horsepower (metric)
    PS
  • Horsepower (electrical)
    hp(E)
  • BTU per hour
    BTU/hr
  • BTU per minute
    BTU/min
  • Kilocalorie per hour
    kcal/hr
  • Foot-pound per second
    ft-lb/s
  • Ton of refrigeration
    RT

How to convert power units

  1. Enter a value

    Type the amount of power you want to convert into the input field.

  2. Pick the source unit

    Choose the unit your value is in, such as watts, kilowatts, or horsepower.

  3. Read every result

    The full list of equivalents updates instantly across all supported power units.

  4. Copy what you need

    Adjust the decimal precision if you like, then copy any single result or the whole table.

Why use this tool

Every unit at once

One value converts to watts, kilowatts, megawatts, milliwatts, horsepower variants, BTU per hour, and more in a single glance.

Both horsepower standards

Mechanical, metric, and electrical horsepower are listed separately so you never mix up the definitions.

Adjustable precision

Set how many decimal places each result shows, from whole numbers to fine engineering detail.

Sensible edge handling

Empty, non-numeric, negative, and very large inputs are handled cleanly with a short hint instead of broken output.

Private by design

Every conversion runs on your own device. Nothing you type is uploaded or stored anywhere.

Free and unlimited

Convert as many values as you want with no account, no limits, and no cost.

About this tool

Power measures how quickly energy is used or produced. The watt is the base unit, defined as one joule per second, and almost every other power unit maps back to it. This converter uses the watt as its pivot so any value you enter can be expressed in every other unit at once, without you chaining calculations by hand.

The tool covers the units engineers, electricians, and gearheads reach for most: watts, kilowatts, megawatts, and milliwatts on the metric side, plus mechanical horsepower, metric horsepower, and electrical horsepower on the imperial and legacy side. It also includes BTU per hour and foot-pounds per second, which show up constantly in heating, cooling, and mechanical work.

Horsepower is the classic trap. Mechanical horsepower is about 745.7 watts, metric horsepower is about 735.5 watts, and electrical horsepower is exactly 746 watts. Quoting the wrong one shifts a result by more than one percent, which matters when you size a motor or compare engine ratings. Listing all three side by side removes the guesswork.

Enter a value, choose its unit, and read the complete table. Raise the precision when you need engineering accuracy or lower it for a quick estimate. For related work try the energy converter for joules and kilowatt hours, or the frequency converter for hertz. Everything happens on your device.

Frequently asked questions

What is the difference between mechanical and metric horsepower?
Mechanical horsepower equals about 745.7 watts and is common in the United States and United Kingdom. Metric horsepower equals about 735.5 watts and is used across much of Europe. This tool lists both so you can pick the right one.
How do I convert kilowatts to horsepower?
Enter your kilowatt value and choose kilowatt as the unit. The result row for mechanical horsepower shows the answer. As a rule of thumb, one kilowatt is roughly 1.34 mechanical horsepower.
Can I convert BTU per hour to watts?
Yes. Choose BTU per hour as the source unit and read the watt row. One BTU per hour is about 0.293 watts, so heating and cooling ratings translate directly.
What happens with negative or empty values?
An empty or non-numeric entry shows a short hint instead of results. Negative values are accepted and converted normally, since power can be expressed as a signed quantity in some contexts.
Is my data sent anywhere?
No. Every calculation runs locally on your device. Nothing you enter is uploaded, logged, or stored, and the tool works without an account.

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