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Power Converter

Power Conversion Calculator

From watts to horsepower, calculate the rate of doing work in any unit.
Power Converter

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      BTU per hour to HorsepowerBTU per hour to KilowattBTU per hour to WattBTU per second to HorsepowerBTU per second to KilowattGigawatt to KilowattGigawatt to MegawattGigawatt to WattHorsepower to BTU per hourHorsepower to KilowattHorsepower to MegawattHorsepower to WattJoule per second to WattKilowatt to BTU per hourKilowatt to BTU per secondKilowatt to Gigawatt
      Updated on September 1, 2025

      About Our Power Conversion Calculator

      Written By
      author
      Nadiba Rahman
      Reviewed by
      author
      Mrinmoy Roy
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      You can use our Power Conversion Calculator to quickly and accurately convert between a variety of units, such as watts to horsepower, kilowatts to BTU/h, calories per second to watts, and more. This tool simplifies the conversion process, making it fast, easy, and free from errors. In this article, I’ll explain how the power conversion calculator works, the range of supported units, and its helpful features. Let’s get started!

      What Is Power?

      Power is the rate at which energy is transferred, used, or converted. It measures how quickly work is done or how fast energy flows through a system. Power is generally expressed as energy per unit of time.

      The basic equation for power is:

      Power (P) = Energy (E) / Time (t)

      Power is measured in different units such as watts (W), horsepower (hp), or joules per second. The watt (W) is the standard power unit in the International System of Units (SI). One watt equals one joule of energy used or transferred in one second (1 W = 1 J/s).

      Conversion Units of Our Power Converter

      In our power converter, we support 19 different power units. Here’s a list of the available units:
      1. BTU per hour (BTU/h): Used in heating and cooling industries. 1 BTU/h is about 0.293 watts.
      2. BTU per minute (BTU/min): Measures heat energy transfer per minute.
      3. BTU per second (BTU/s): It represents a rapid rate of heat energy transfer. 1 BTU/s equals about 1,055 watts.
      4. Calorie per hour (cal/h): 1 cal/h equals roughly 0.00116 watts.
      5. Calorie per minute (cal/min): Equal to about 0.0697 watts.
      6. Calorie per second (cal/s): Used in thermodynamics. 1 cal/s is equal to about 4.184 watts.
      7. Foot-pound per minute (ft-lb/min): Equal to about 0.0226 watts.
      8. Foot-pound per second (ft-lb/s): Used in mechanical systems. 1 ft-lb/s equals approximately 1.3558 watts.
      9. Gigawatt (GW): Used to measure the capacity of very large power facilities. 1 GW equals 1,000 megawatts.
      10. Horsepower (hp): Generally used to measure the power of engines. One horsepower is equal to 746 watts.
      11. Joule per hour (J/h): 1 J/h equals about 0.000278 watts.
      12. Joule per minute (J/min): Equal to the total energy transferred per minute. 1 J/min equals about 0.0167 watts.
      13. Joule per second (J/s): This is the SI unit of power, equivalent to one watt.
      14. Kilocalorie per hour (Kcal/h): Equal to about 1.163 watts.
      15. Kilocalorie per minute (Kcal/min): Used in fitness and metabolic measurements. 1 kcal/min equals about 69.78 watts.
      16. Kilowatt (kW): Kilowatts are used to express larger amounts of power. 1 kW equals 1,000 watts.
      17. Megawatt (MW): Equal to 1,000 kilowatts.
      18. Ton of refrigeration (TR): Used to quantify the cooling capacity of refrigeration systems. 1 TR equals 3.517 kW.
      19. Watt (W): Watt is the SI unit of power. One watt is equivalent to one joule of energy per second.

      How to Use Our Power Conversion Calculator?

      Using our online power converter is very simple and fast. Here’s a step-by-step guide:

      Select Source and Target Units

      Select the units you want to convert from and to. For example, you want to convert Watts to Horsepower.
      Select input and output power units
      The moment you select the units, a real-time formula preview appears to help you understand how the conversion between the selected units is done.

      Select Source and Target Units

      Select the units you want to convert from and to. For example, you want to convert Watts to Horsepower.
      Enter the input power value

      Select Source and Target Units

      Select the units you want to convert from and to. For example, you want to convert Watts to Horsepower.
      Get the converted power value

      Features of Our Power Conversion Calculator

      Our power conversion calculator has powerful features to simplify complex power unit conversions and make your workflow smoother. You can easily access all these features from the settings menu. Here’s how each feature supports your power conversion tasks:

      Real-Time Multi-Unit Conversion

      When working with power values, it’s common to need the results in multiple units at once, like watts, horsepower, or BTUs/hr. Converting these manually takes time and can lead to mistakes. That’s why our calculator updates all equivalent power units in real-time as soon as you enter a number, saving you time and helping you cross-check data quickly.
      Real-time multi-unit conversion

      Flexible Decimal Precision

      In power calculations, especially for motors, heating systems, or electrical loads, even small decimal differences can affect performance analysis and system sizing. Our calculator lets you choose how many decimal places to display, from 0 to 12. The default is 6 decimal places, but you can increase it for more precise results when needed.

      For example, if you convert 10 horsepower (hp) to watts, setting the precision to 9 decimal places will give you 7456.998715823 watts instead of just 7456.998716 watts.

      Rounding Mode Control

      Power conversion often needs exact rounding for design specifications or compliance testing. Even small rounding differences can affect electrical load distribution or energy efficiency calculations. That’s why we’ve added a rounding mode control feature. You can choose to round up, round down, or turn off rounding entirely. This ensures your converted power values meet your project’s needs and avoids costly miscalculations.

      Multiple Number Formats

      Power values can range from milliwatts to megawatts, and without the right format, these numbers can be hard to read or share. Our calculator offers three display options to fit your needs:
      1. Standard Decimal (like 1,000 W)
      2. Scientific Notation (like 1.0e+3)
      3. Engineering Format (like 1.0 × 10^3 W)
      For example, converting 2.5 megawatts (MW) can appear as 2,500,000 W in standard decimal, 2.5e+6 in scientific notation, or 2.5 × 10^6 W in engineering format. This flexibility makes it easier to understand and share data in your reports.

      Integrated Scientific Calculator

      Suppose you need to calculate the total power for several machines or adjust for power factors. Switching to another calculator can slow you down and cause errors. That’s why our tool includes a built-in scientific calculator.

      You can perform quick calculations right inside the tool and then convert the final result to the unit you need in one place.
      Built-in Scientific calculator

      Thousand Separators Toggle

      Large power values can be tricky to read and easy to misinterpret. Our thousand separators toggle adds commas to your numbers, so 1234567 W becomes 1,234,567 W. This makes the values clearer and helps reduce mistakes in your calculations.

      One-click Unit Swap

      Sometimes you need to check conversions both ways, like from kilowatts to horsepower and then back again. Our one-click unit swap instantly flips the input and output units with a single click, making it simple to verify or compare your results quickly.

      Auto-Saved Conversion History

      Doing many power conversions? It’s easy to forget past results. Our calculator automatically saves the last 10 conversions, even if you refresh or close your browser. All you need to do is open the History tab and click on any previous entry to load it instantly. This helps keep your work organized and saves you from re-entering data.
      Recent 10 conversion records

      Power Conversion Table

      Click the button below to download the power conversion chart. It provides conversion factors for all your power calculations

      3 Examples of Conversion With Our Power Converter

      To convert power units accurately, you need to know the source unit, the target unit, and the correct conversion factor (you can find these in the Power Conversion Chart above). Here’s the simple formula:

      Value of Target Unit = Conversion Factor × Value of Source Unit

      Here are three examples to help you understand how it works:

      BTU per hour (BTU/h) to Watts (W) Conversion

      To convert BTU/h to W, multiply the BTU/h value by the conversion factor 0.293071. For example, to convert 1500 BTU/h to watts:
      1000 × 0.293071 = 293.071 watts
      Conversion between BTU per hour and Watts
      For reverse conversion (W to BTU/h), multiply the watt value by 3.412142.

      Horsepower (hp) to Kilowatts (kW) Conversion

      To convert hp to kW, multiply the horsepower value by 0.7457. For example, to convert 10 hp to kilowatts:
      10 × 0.7457 = 7.457 kW
      Conversion between Horsepower and Kilowatts
      For reverse conversion (kW to hp), multiply the kilowatt value by 1.341022.

      Kilocalorie per hour (kcal/h) to Watts (W) Conversion

      To convert kcal/h to W, multiply the kcal/h value by 1.16222. For example, to convert 1500 kcal/h to watts:
      1500 × 1.16222 = 1743.33 watts
      Conversion between Kilocalorie per hour and Watts
      For reverse conversion (W to kcal/h), multiply the watt value by 0.860422.

      Conclusion

      So far, you’ve learned the ins and outs of our power conversion calculator. Its user-friendly interface and powerful features let you convert power units quickly, accurately, and without hassle. Forget about manual conversion - try our tool and make your power conversions faster, easier, and error-free!
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      Frequently Asked Questions [FAQs]