Power Converter

Convert a power value between watts, kilowatts, megawatts, horsepower variants, BTU per hour, and other power units. All conversions go through the SI base unit (the watt) so the math stays exact and reproducible.

Supported power units

• SI prefixes: milliwatt (mW), watt (W), kilowatt (kW), megawatt (MW), gigawatt (GW).
• Horsepower: mechanical (hp, 745.6998715822702 W), metric (PS, 735.49875 W), electrical (746 W), and boiler (9809.5 W).
• Thermal: BTU/h, kBTU/h, calorie per second, kilocalorie per hour.
• Mechanical work rates: foot-pound per second, foot-pound per minute, joule per second, kilojoule per hour, erg per second.

How conversions work

Power is the rate at which energy is transferred. One watt equals one joule per second:

\[ 1\,\text{W} = 1\,\frac{\text{J}}{\text{s}} \]

To convert from a unit \(U_1\) with watt factor \(f_1\) to \(U_2\) with watt factor \(f_2\):

\[ \text{value}_{U_2} = \text{value}_{U_1} \times \frac{f_1}{f_2} \]

Common reference values

• \(1\,\text{hp (mechanical)} = 745.6998715822702\,\text{W}\)
• \(1\,\text{PS (metric)} = 735.49875\,\text{W}\)
• \(1\,\text{kW} = 1{,}000\,\text{W}\)
• \(1\,\text{BTU/h} \approx 0.293071\,\text{W}\)
• \(1\,\text{kcal/h} = 1.163\,\text{W}\)

When to use this tool

• Sizing motors, generators, and electrical loads when datasheets mix horsepower with kilowatts.
• Comparing HVAC heating and cooling output expressed in BTU/h against electrical input in W.
• Converting solar panel and inverter ratings between W and kW.
• Checking energy budgets in physics homework or engineering calculations.