Power Conversion - Convert Watts, Horsepower, BTU/hour, and More
Power Converter
Convert power measurements between different units quickly and accurately
Convert Power
Popular Power Conversions
Quickly convert between the most commonly used power units.
Understanding Power Measurements
Power conversions are essential for various applications, from small electronics and IoT devices to massive power plants and industrial systems. Understanding power conversions across the full spectrum—from milliwatts to gigawatts—ensures accurate and consistent results in engineering, HVAC, energy management, and scientific applications.
Common Power Units
Small Scale Units
- Milliwatt (mW) - Electronics, IoT
- Watt (W) - Household appliances
- Kilowatt (kW) - Major appliances
Large Scale Units
- Megawatt (MW) - Industrial, wind turbines
- Gigawatt (GW) - Power plants, national grids
Mechanical Units
- Mechanical Horsepower (hp) - US/Imperial
- Metric Horsepower (PS) - European
- Foot-pound per Second (ft·lb/s)
HVAC & Industrial Units
- Tons of Refrigeration (TR) - Cooling systems
- Boiler Horsepower (BHP) - Steam boilers
- British Thermal Unit per Hour (BTU/h IT)
Common Applications
| Field | Typical Units | Common Range |
|---|---|---|
| Electronics & IoT | mW, W | 1mW - 100W |
| Household Appliances | W, kW | 10W - 5kW |
| Automotive | hp, kW | 100-500 hp |
| HVAC Systems | TR, BHP, kW | 2-1000 TR |
| Industrial Equipment | kW, MW, BHP | 10kW - 100MW |
| Power Plants | MW, GW | 100MW - 10GW |
| Renewable Energy | kW, MW, GW | 5kW - 5GW |
Conversion Tips
- Use a calculator for precise power conversions
- For quick estimates: 1 mechanical horsepower = 745.7 watts
- For quick estimates: 1 metric horsepower (PS) = 735.5 watts
- For HVAC: 1 ton of refrigeration = 12,000 BTU/hr (IT) = 3.517 kW
- For industrial: 1 boiler horsepower = 33,475 BTU/hr (IT) = 9.81 kW
- Remember: 1 kW = 1,000 W, 1 MW = 1,000 kW, 1 GW = 1,000 MW
- For electronics: 1,000 mW = 1 W
Power Conversions
| Conversion | Formula/Rule | Quick Answer |
|---|---|---|
| Milliwatts to Watts | 1 W = 1,000 mW | Divide mW by 1,000 |
| Watts to Kilowatts | 1 kW = 1,000 W | Divide W by 1,000 |
| Megawatts to Gigawatts | 1 GW = 1,000 MW | Divide MW by 1,000 |
| Watts to Mechanical Horsepower | 1 hp = 745.7 W | Divide W by 745.7 |
| Mechanical Horsepower to Watts | 1 W = 0.00134 hp | Multiply hp by 745.7 |
| Watts to Metric Horsepower | 1 PS = 735.5 W | Divide W by 735.5 |
| Metric Horsepower to Watts | 1 W = 0.00136 PS | Multiply PS by 735.5 |
| BTU/hr to Tons of Refrigeration | 1 TR = 12,000 BTU/hr (IT) | Divide BTU/hr by 12,000 |
| kW to Boiler Horsepower | 1 BHP = 9.81 kW | Divide kW by 9.81 |
| Watts to BTU/h | 1 BTU/h (IT) = 0.293 W | Divide W by 0.293 |
| BTU/h to Watts | 1 W = 3.412 BTU/h (IT) | Multiply BTU/h by 0.293 |
| Watts to Foot-pounds per Second | 1 ft·lb/s = 1.356 W | Divide W by 1.356 |
Our comprehensive power conversion tool covers the full spectrum from milliwatts to gigawatts, supporting electronics, HVAC, industrial, automotive, and energy applications. Whether you're designing IoT devices, sizing HVAC systems, or planning renewable energy projects, our converter provides accurate conversions for any power-related calculation.
Power Conversion Questions
Everything you need to know about power measurements and conversions
What's the difference between power and energy?
Power is the rate of energy transfer, measured in watts (joules per second). Energy is the total amount of work done, measured in joules or kilowatt-hours. Think of power as the speedometer of energy—it tells you how fast energy is being used, not how much total energy has been consumed.
Why are there different types of horsepower?
Mechanical horsepower (745.7W) is the US/Imperial standard, originally defined by James Watt for steam engines. Metric horsepower (735.5W, also called PS or Pferdestärke) is the European standard, defined as 75 kilogram-force meters per second. The metric version is about 1.4% smaller than mechanical horsepower. Always specify which type when comparing engine outputs.
What are tons of refrigeration and when are they used?
Tons of refrigeration (TR) measure cooling capacity, not weight. One TR equals 12,000 BTU/hour (IT) or 3,517 watts, representing the cooling power needed to freeze one ton of ice in 24 hours. It's the standard unit in HVAC for air conditioning systems—a typical home AC unit is 2-5 TR, while large commercial systems can be 100-1000 TR.
What is boiler horsepower and how does it differ from mechanical horsepower?
Boiler horsepower (BHP) measures the power output of steam boilers and heating systems. One BHP equals 33,475 BTU/hour (IT) or 9,810 watts—about 13 times larger than mechanical horsepower. It was originally defined as the power needed to evaporate 34.5 pounds of water per hour. Industrial boilers typically range from 10-1000 BHP.
When should I use milliwatts vs watts vs kilowatts?
Use milliwatts (mW) for small electronics: Bluetooth chips (~10mW), LEDs (~20mW), IoT sensors. Use watts (W) for household items: light bulbs (10-100W), laptops (65W), small appliances. Use kilowatts (kW) for major appliances and systems: electric ovens (3kW), air conditioners (3-5kW), car engines (100-300kW).
What's the difference between megawatts and gigawatts?
Megawatts (MW) are used for large systems: wind turbines (2-3MW), solar farms (10-100MW), small power plants (100-500MW). Gigawatts (GW) are for massive power generation: large nuclear plants (1-1.5GW), country-level renewable projects (1-10GW), national grid capacity (100-1000GW). 1 GW = 1,000 MW.
How do I calculate my home's power consumption?
Add up the wattage of all running appliances. Common examples: LED bulb 10W, laptop 65W, refrigerator 150W, electric oven 3000W, air conditioner 3500W. Multiply total watts by hours of use to get energy consumption in watt-hours (Wh).
What does '15 amp circuit' mean in terms of power?
In the US (120V), a 15-amp circuit can safely handle 15A × 120V = 1,800 watts continuous load (80% of capacity for safety). A 20-amp circuit handles 2,400W. European circuits (230V) with 16A can handle about 3,680W. Never exceed circuit capacity to avoid tripping breakers or fire hazards.
How much power do electric vehicles use?
Electric cars typically use 250-400 Wh per mile. A Tesla Model 3 uses about 300 Wh/mile, so a 100-mile trip requires 30 kWh. Home Level 2 chargers provide 7-11 kW, while DC fast chargers can deliver 50-350 kW for rapid charging.
Why do appliances show different power ratings?
Appliances may list peak power (maximum), average power (typical use), or standby power (when 'off'). A microwave might show 1000W (cooking power) and 1500W (electrical input power). Always check if the rating is input power (from wall) or output power (useful work).
How do I convert between BTU/hour and watts for heating/cooling?
1 BTU/hour (IT) = 0.293 watts. Air conditioners and heaters often use BTUs. A 12,000 BTU/hour (IT) air conditioner uses about 3,516 watts (3.5 kW). This conversion helps compare energy efficiency between different HVAC systems.
What's the relationship between voltage, current, and power?
Power = Voltage × Current (P = V × I). In AC circuits, this becomes more complex due to power factor. A 120V circuit drawing 10A consumes 1,200W. Understanding this relationship helps with electrical safety and sizing electrical components.
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