Watt Calculator
Calculate power in watts (W) from voltage, current, and power factor.
Power (Watts) Calculator
Understanding Watts (W)
Watts (W) are the unit of real power, representing the rate at which electrical energy is converted into another form of energy (like heat, light, or motion). It is a fundamental unit in electrical engineering.
Watt Calculation Formulas
Watts (P) = Volts (V) × Amps (I)
For AC Single-Phase Circuits:
Watts (P) = Volts (V) × Amps (I) × Power Factor (PF)
For AC Three-Phase Circuits:
Watts (P) = √3 × Volts (V) × Amps (I) × Power Factor (PF)
Where:
• P = Power in Watts
• V = Voltage in Volts
• I = Current in Amperes
• PF = Power Factor (between 0 and 1)
• √3 ≈ 1.732
Key Concepts
- Watt (W): The unit of real power.
- Volt (V): The unit of electric potential difference.
- Ampere (A): The unit of electric current.
- Power Factor (PF): The ratio of real power to apparent power in AC circuits.
Typical Power Consumption of Devices
| Device | Approximate Power (Watts) |
|---|---|
| LED Light Bulb | 5 - 15 W |
| Laptop Charger | 45 - 90 W |
| Desktop Computer | 100 - 400 W |
| Microwave Oven | 600 - 1500 W |
| Electric Water Heater | 2000 - 5000 W |
Frequently Asked Questions
What is the difference between Watts and Joules?
Watts measure power (the rate of energy transfer or consumption), while Joules measure energy (the total amount of work done or energy consumed). One Watt is equal to one Joule per second (1 W = 1 J/s).
How does power factor affect Watt calculation?
In AC circuits, the power factor accounts for the portion of apparent power that actually performs work. A power factor of 1 (or close to 1) indicates efficient use of power, while a lower power factor means more current is needed to deliver the same amount of real power (Watts).