Electrical Power Calculator
Calculate power (Watts), voltage (Volts), current (Amps), or power factor for Direct Current (DC), single-phase AC, and three-phase AC electrical systems.
Electrical Power Calculation Formulas
Electrical power is the rate at which electrical energy is transferred by an electric circuit per unit of time. Depending on whether you are working with DC or AC systems, the formula adjusts for phase angles and power factors.
Core Formulas
For Direct Current (DC) Circuits:
$$P = V \cdot I$$For Single-Phase AC Circuits:
$$P = V \cdot I \cdot \text{PF}$$For Three-Phase AC Circuits:
$$P = \sqrt{3} \cdot V \cdot I \cdot \text{PF}$$Apparent Power (\(S\)):
$$S = V \cdot I \quad (\text{Single Phase}) \qquad S = \sqrt{3} \cdot V \cdot I \quad (\text{Three Phase})$$Where:
- P = Active Real Power in Watts (W)
- S = Apparent Power in Volt-Amperes (VA)
- V = Line Voltage in Volts (V)
- I = Current in Amps (A)
- PF = Power Factor (\(\cos\phi\)), dimensionless ratio between 0 and 1.0
Frequently Asked Questions
How do you calculate electrical power?
Electrical power is calculated using Ohm's Law and AC power formulas: \(P = V \times I\) for DC circuits, \(P = V \times I \times \text{PF}\) for single-phase AC, and \(P = \sqrt{3} \times V \times I \times \text{PF}\) for three-phase AC circuits.
What is Power Factor (PF)?
Power factor is the ratio of active real power (Watts) to apparent power (Volt-Amperes). It represents the efficiency of power consumption in AC electrical systems and typically ranges between 0 and 1.0.
What is the difference between Active Power and Apparent Power?
Active power (kW or W) is the real power used to run electrical equipment. Apparent power (kVA or VA) represents the total power supplied to the circuit, including reactive power stored in inductive or capacitive fields.