Power Converter Guide
Understanding Power Units
Power measures the rate of energy transfer or work done over time. Different industries use various power units based on historical development and practical applications.
Common Power Units
- Watts (W): SI base unit of power
- Kilowatts (kW): 1,000 watts
- Horsepower (hp): Mechanical power unit
- BTU/hr: Heat transfer rate
- Calories/second: Metabolic power
Key Conversions
- 1 hp = 746 watts = 0.746 kW
- 1 kW = 1.34 hp = 3,412 BTU/hr
- 1 BTU/hr = 0.293 watts
- 1 cal/s = 4.184 watts
- 1 MW = 1,341 horsepower
Professional Applications
Electrical Systems
- • Appliance power ratings
- • Motor specifications
- • Generator capacity
- • Solar panel output
Automotive Engineering
- • Engine power ratings
- • Electric vehicle motors
- • Performance comparisons
- • Fuel efficiency calculations
HVAC Systems
- • Heating capacity
- • Cooling load calculations
- • Energy efficiency ratings
- • System sizing
Industrial Equipment
- • Pump and compressor sizing
- • Manufacturing equipment
- • Power plant capacity
- • Energy management
Power vs Energy Distinction
Power (Rate)
- • How fast energy is used
- • Measured in watts, horsepower
- • Instantaneous measurement
- • Motor nameplate ratings
Energy (Total)
- • Total energy consumed
- • Measured in kWh, BTU
- • Power × time
- • Electricity bills
Common Power Examples
Household Appliances
Vehicles & Machinery
Regional Unit Preferences
United States
Uses horsepower for engines and motors, BTU/hr for HVAC, and watts for electrical devices.
International (Metric)
Primarily uses watts and kilowatts for all power applications, following SI standards.
Scientific Community
Universally uses watts as the standard SI unit for power in all scientific applications.
Step-by-Step Power Conversion
- 1. Identify Source Unit: Determine whether you have watts, horsepower, or BTU/hr
- 2. Enter Power Value: Input the power rating from equipment nameplate
- 3. Select Target Unit: Choose the unit needed for your application
- 4. Verify Context: Ensure the conversion makes sense for your equipment type
- 5. Apply Safety Factors: Consider efficiency and safety margins for sizing
Frequently Asked Questions
Why is horsepower still used when watts are the SI standard?
Historical reasons and consumer familiarity. Automotive and industrial sectors developed using horsepower, and consumers understand it better for comparing engine performance.
How do I calculate electricity costs from power ratings?
Multiply power (kW) by usage time (hours) to get energy (kWh), then multiply by your electricity rate ($/kWh). Example: 1.5 kW × 8 hours × $0.12/kWh = $1.44.
What's the difference between mechanical and electrical horsepower?
Mechanical horsepower (746 watts) is the standard. Electrical horsepower varies slightly. Our converter uses mechanical horsepower as the standard reference.
How does power factor affect electrical power calculations?
Power factor affects AC electrical systems but doesn't change unit conversions. Our converter shows mechanical/thermal power equivalents, not electrical power calculations.