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Power Converter

Popular Power unit conversions

Power Converter — Convert Watts, Horsepower, BTU/hr & More

Our free online Power Converter lets you instantly convert between 75+ units of power — from everyday watts and kilowatts to horsepower, BTU/hour, and calorie-based units. Whether you need to convert watts to horsepower, kilowatts to BTU/hr, horsepower to watts, or megawatts to kilocalories per second, this tool delivers fast and accurate results.

Power is the rate at which energy is transferred or work is done. It is expressed in many units depending on the discipline:

  • SI metric: watt (W), kilowatt (kW), megawatt (MW), gigawatt (GW), terawatt (TW)
  • Mechanical: horsepower (hp), metric horsepower (PS), foot-pound per second/minute
  • Thermal: BTU per hour/minute/second, kilocalorie per hour/second, calorie per hour/second
  • Electrical: volt-ampere (VA), kilovolt-ampere (kVA), joule per second (J/s)
  • Refrigeration: ton of refrigeration

All conversions use internationally standardized SI factors, making this tool reliable for electrical engineering, HVAC, automotive, manufacturing, and everyday power calculations.

Common Power Conversion Reference

Here are the most frequently used power conversions for quick reference:

  • 1 horsepower (UK/US) = 745.7 watts = 0.7457 kW = 2,544.43 BTU/hr
  • 1 metric horsepower (PS) = 735.499 watts = 0.7355 kW
  • 1 kilowatt = 1,000 watts = 1.341 horsepower = 3,412 BTU/hr
  • 1 watt = 1 joule/second = 0.001 kilowatts = 3.412 BTU/hr
  • 1 BTU/hour = 0.293071 watts = 0.000393 horsepower
  • 1 ton of refrigeration = 3,516.85 watts = 12,000 BTU/hr
  • 1 kilocalorie/hour = 1.163 watts
  • 1 megawatt = 1,000 kW = 1,341 horsepower

Frequently Asked Questions — Power Converter

Question: How do I use the Power Converter?

Answer: Select the unit you are converting from in the left list and the unit to convert to in the right list, then type your value. The result appears instantly across all listed units.

Question: What is the difference between a watt and a kilowatt?

Answer: A kilowatt (kW) equals exactly 1,000 watts (W). Watts measure power (the rate of energy use), while kilowatt-hours (kWh) measure energy (power over time). Your electricity bill uses kilowatt-hours, but your appliances are rated in watts or kilowatts.

Question: How many watts are in one horsepower?

Answer: One mechanical horsepower (hp) equals 745.6999 watts. One metric horsepower (PS or CV) equals 735.49875 watts. The metric horsepower is used in Europe for vehicle engine ratings; the mechanical horsepower is used in the US.

Question: How do I convert kilowatts to horsepower?

Answer: Multiply the kilowatt value by 1.34102 to get mechanical horsepower (US). For example, 100 kW × 1.34102 = 134.1 hp. For metric horsepower, multiply by 1.35962.

Question: What is a BTU per hour?

Answer: BTU/hour (Btu/h) is a measure of thermal power — the rate of heat transfer. One BTU/hr equals 0.293071 watts. It is commonly used for air conditioner and heating system ratings in the US.

Question: What does a ton of refrigeration mean?

Answer: A ton of refrigeration is the power needed to freeze one short ton (2,000 lbs) of water at 32°F in 24 hours. It equals 12,000 BTU/hr or approximately 3,516.85 watts (3.517 kW). It is the standard rating for air conditioners in the US.

Question: How many watts are in a megawatt?

Answer: One megawatt (MW) equals exactly 1,000,000 watts (1,000 kW). Power plants and solar farms are typically rated in megawatts or gigawatts (GW = 1,000 MW = 1,000,000,000 W).

Question: What is a volt-ampere (VA) and how does it differ from a watt?

Answer: In DC circuits, volt-amperes and watts are identical. In AC circuits, watts measure real power while VA (volt-amperes) measures apparent power. The ratio between them is the power factor. For purely resistive loads, 1 VA = 1 W.

Question: How accurate are the power conversions in this tool?

Answer: All conversions use internationally standardized conversion factors with up to 12 significant digits of precision, suitable for electrical engineering, mechanical engineering, HVAC, and scientific applications.