Power Conversion Calculator

Fast and reliable conversion between electrical, mechanical, and thermal power units, including Watts, Horsepower, and BTUs.

Calculation Examples

Calculation Case Result
Electric Motor: 5 kW to Mechanical Horsepower 6.705 hp
Car Engine: 150 hp to Kilowatts 111.85 kW
Air Conditioner: 12000 BTU/hr to Watts 3516.85 W

How to Use the Power Conversion Calculator?

The power conversion calculator is designed to provide instant results for both industrial and domestic power transformations. To begin, enter the numerical value you wish to convert in the input field. Select your starting unit from the "From" menu — options include standard SI units like the Watt (W) and Kilowatt (kW), as well as specialized units like Mechanical Horsepower (hp) and BTU per hour (BTU/hr).

Next, choose your target unit from the "To" menu. The converter applies the formula: $$P_{target} = P_{source} \times \text{Conversion Factor}$$. The result is displayed instantly in the output field, often including a breakdown of the calculation path. Whether you are sizing an electrical breaker, evaluating an engine's performance, or calculating HVAC heating loads, our tool ensures mathematical accuracy across different measurement systems.

Technical Standards in Power Unit Conversions

Power is defined as the rate at which work is performed or energy is transferred. In the International System of Units (SI), the Watt (W) is the base unit, equivalent to one Joule per second ($1 \text{ W} = 1 \text{ J/s}$). All conversions within this tool are verified against the standard definitions maintained by NIST and the BIPM.

Mechanical power measurement often relies on "Horsepower," a unit with multiple definitions. Our calculator differentiates between Mechanical (Imperial) Horsepower ($ \approx 745.7 \text{ W} $) and Metric Horsepower ($ \approx 735.5 \text{ W} $). For thermal applications, we use the International Steam Table BTU, where $1 \text{ BTU/hr}$ is approximately $0.293 \text{ Watts}$. These precise factors prevent cumulative errors in engineering blueprints and technical specifications.

Power unit conversion factors: Watts, Kilowatts, Horsepower, and BTU per hour chart

Useful Tips 💡

  • For high-voltage systems, Megawatts (MW) are standard, while consumer electronics use Watts (W).
  • Confirm if your source uses Metric Horsepower (PS) or Imperial Horsepower (hp) as they differ by 1.4%.
  • Remember: Power is a rate; multiplying it by time gives Energy (e.g., $1 \text{ kW} \times 1 \text{ h} = 1 \text{ kWh}$).

📋Steps to Calculate

  1. Enter the numerical power value into the input box.

  2. Select the source unit (e.g., kW, hp, or BTU/hr) from the first dropdown.

  3. Select the target unit from the second dropdown menu.

  4. View the converted result instantly with high decimal precision.

Mistakes to Avoid ⚠️

  1. Mixing up Mechanical hp (745.7 W) with Metric PS (735.5 W).
  2. Confusing Power (Watts) with Energy (Watt-hours).
  3. Assuming 1 BTU/hr equals 1 Watt; in reality, 1 Watt is over 3 times larger.
  4. Using approximate rounded values for critical engineering specifications.

Practical Applications📊

  1. Electrical Engineering: Convert Watts to Kilowatts for circuit load balancing and energy billing.

  2. Automotive Industry: Translate engine output between Kilowatts (kW) and Mechanical Horsepower (hp).

  3. HVAC Systems: Convert BTU/hr to Kilowatts to determine cooling capacity and energy efficiency.

  4. Industrial Machinery: Sizing motors by converting electrical input (W) to mechanical output (hp).

Questions and Answers

What is a power conversion calculator and why is it essential?

A power conversion calculator is a technical tool used to translate the rate of energy transfer between different measurement systems. Since power definitions vary, electrical, mechanical, or thermal-mental calculation is prone to error. Our tool ensures engineers maintain the precision required for safety standards and system compatibility.

How do I convert Watts to Kilowatts accurately?

To convert Watts (W) to Kilowatts (kW), divide the value by 1,000. The formula is: $$ P_{(kW)} = \frac{P_{(W)}}{1000} $$ This is a standard metric prefix conversion where "kilo" represents $10^3$, essential for electrical utility billing and load assessment.

What is the difference between Mechanical and Metric Horsepower?

Mechanical Horsepower (hp) is $550 \text{ ft-lb/s} \approx 745.7 \text{ W}$, while Metric Horsepower (PS) is the power to lift $75 \text{ kg}$ by $1 \text{ m}$ in $1 \text{ s} \approx 735.5 \text{ W}$. Formulas: $$ 1 \text{ hp} \approx 745.7 \text{ W} $$ and $$ 1 \text{ PS} \approx 735.5 \text{ W} $$.

How do you convert Horsepower to Watts for motors?

To convert mechanical horsepower to electrical Watts, multiply the HP value by 745.7. For example, a 2 hp motor: $$ 2 \text{ hp} \times 745.7 = 1491.4 \text{ W} $$ This helps in determining the necessary wire gauge and fuse size for installations.

What is the conversion factor from BTU/hr to Watts?

BTU per hour is used in HVAC. The conversion to Watts is: $$ 1 \text{ BTU/hr} \approx 0.29307 \text{ W} $$ This factor is used to compare cooling capacity against electrical consumption in Watts for energy efficiency ratings.

Is the Watt an SI unit and how is it defined?

Yes, the Watt (W) is the SI unit of power. It is defined as one Joule per second ($1 \text{ J/s}$). In electrical terms: $$ 1 \text{ W} = 1 \text{ J/s} = 1 \text{ V} \cdot \text{A} $$ It measures the rate of energy conversion or transfer.

Which international standards does this power converter follow?

This converter adheres to the mathematical constants defined by the BIPM and NIST. These standards ensure that whether converting Megawatts to BTU/hr or Metric Horsepower to Kilowatts, the results are valid for scientific research and engineering reports.

What are the most common power conversion factors for engineering units?

To assist with rapid technical calculations, here is a reference table of the most frequently used power conversion factors, ranging from micro-electronics to heavy industry and thermal HVAC systems:

UnitSymbolValue in Watts (W)Scientific Notation
PicowattpW0.000000000001 W$10^{-12}$ W
NanowattnW0.000000001 W$10^{-9}$ W
MicrowattµW0.000001 W$10^{-6}$ W
MilliwattmW0.001 W$10^{-3}$ W
KilowattkW1,000 W$10^{3}$ W
MegawattMW1,000,000 W$10^{6}$ W
GigawattGW1,000,000,000 W$10^{9}$ W
TerawattTW1,000,000,000,000 W$10^{12}$ W
PetawattPW1,000,000,000,000,000 W$10^{15}$ W
BTU per hourBtu/h0.293071 W-
Mechanical Horsepowerhp(I)745.699 W-
Metric Horsepowerhp(M) / PS735.498 W-
Electric Horsepowerhp(E)746 W-
Boiler Horsepowerhp(S)9812.5 W-
Ton of RefrigerationTR3516.852 W-

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Disclaimer: This calculator is designed to provide helpful estimates for informational purposes. While we strive for accuracy, financial (or medical) results can vary based on local laws and individual circumstances. We recommend consulting with a professional advisor for critical decisions.