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The Power Converter (General) is a universal tool for converting between all major units of power. Whether you need to convert watts to horsepower, BTU/hr to kilowatts, or any other combination, this converter handles it instantly with engineering precision.
Power measures the rate at which energy is transferred, used, or generated. The SI unit of power is the watt (W), defined as one joule per second. However, numerous other power units are in active use: horsepower dominates in automotive and mechanical engineering, BTU/hr is standard in HVAC, tons of refrigeration rate air conditioning systems, and volt-amperes describe electrical apparent power.
This universal converter supports 10 common power units spanning from tiny (ergs/sec) to industrial (megawatts). Each conversion passes through watts as the intermediate unit, ensuring consistency. The converter uses internationally standardized conversion factors from NIST, IEEE, and ASHRAE.
Understanding power conversions is critical across engineering disciplines. Mechanical engineers must convert between watts and horsepower for motor specifications. HVAC engineers routinely convert between BTU/hr, tons of refrigeration, and kilowatts. Electrical engineers work with both watts and volt-amperes, understanding the role of power factor in AC circuits.
The diverse landscape of power units reflects the historical development of engineering. James Watt introduced horsepower in the 1780s to market steam engines. BTU/hr emerged from heating engineering. Tons of refrigeration originated from the ice-harvesting industry. Despite SI standardization, these legacy units remain deeply embedded in their respective industries.
The converter works by first converting the input value to watts (the SI unit of power), then converting from watts to the target unit. Key conversion factors to watts: 1 HP = 745.7 W (mechanical), 1 BTU/hr = 0.293071 W, 1 ton of refrigeration = 3516.853 W, 1 ft·lbf/min = 0.022597 W, 1 cal/s = 4.184 W, 1 erg/s = 10⁻⁷ W, 1 VA = 1 W (at unity power factor).
When interpreting results, consider the application context. For electric motors, compare mechanical HP output to electrical kW input. For HVAC, note that tons of refrigeration measure cooling capacity, not electrical input. For AC circuits, VA and watts differ by the power factor (W = VA × PF).
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150 HP ≈ 112 kW
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5 tons = 60,000 BTU/hr
The watt (W), defined as one joule per second. Named after James Watt, inventor of the modern steam engine.
One mechanical horsepower = 745.7 watts. Electrical horsepower = 746 watts. Metric horsepower (PS) = 735.499 watts. This converter uses mechanical HP.
Watts measure real (active) power — the power that does actual work. Volt-amperes measure apparent power in AC circuits. They differ by the power factor: W = VA × PF.
Divide BTU/hr by 12,000. One ton of refrigeration = 12,000 BTU/hr. A 60,000 BTU/hr AC unit = 5 tons.
A ton of refrigeration (TR) = 12,000 BTU/hr ≈ 3.517 kW. It represents the cooling power of melting one ton (2000 lbs) of ice in 24 hours.
Horsepower remains the standard for rating engines and motors in the US and UK due to historical convention. International standards prefer kilowatts.
Multiply kW by 3412.14. For example, 10 kW = 34,121.4 BTU/hr.
Power factor (PF) is the ratio of real power (W) to apparent power (VA) in an AC circuit. PF = cos(phase angle). PF = 1.0 for purely resistive loads.
A typical US household uses 1–2 kW average (about 30 kWh/day). Peak demand during summer (AC) can reach 5–10 kW.
Power is the rate of energy transfer (watts = joules/second). Energy is the total amount transferred (joules = watts × seconds). Running 1 kW for 1 hour uses 1 kWh of energy.
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