P = U * I
P = R * I²
P = U² / R
P = U₀ * I * cosφ
P = Z * I² * cosφ
P = R * I²
P = (U₀² * cosφ) / Z
P = (U₀² * cosφ²) / R
P = S * cosφ
P = Q / tanφ
P = √(S² - Q²)
P = U * I * cosφ
P = Z * I² * cosφ
P = R * I²
P = (U² * cosφ) / Z
P = (U² * cosφ²) / R
P = S * cosφ
P = Q / tanφ
P = √(S² - Q²)
P = √3 * U * I * cosφ
P = √3 * Z * I² * cosφ
P = √3 * R * I²
P = (√3 * U² * cosφ) / Z
P = (√3 * U² * cosφ²) / R
P = S * cosφ
P = Q / tanφ
P = √(S² - Q²)
P = Active power (W)
S = Apparent power (VA)
Q = Reactive power (VAr)
I = Current (A)
U₀ = Voltage [L - N] (V)
U = Voltage [L - L] (V)
R = Resistance (Ω)
Z = Impedance (Ω)
cosφ = Power factor
Active power, also known as real power, is the portion of electrical power that performs useful work in a circuit—such as producing heat, light, or mechanical motion. Measured in watts (W) or kilowatts (kW), it represents the actual energy consumed by a load and is the basis for electricity billing.
This tool calculates active power based on voltage, current, power factor, apparent power, reactive power, resistance, or impedance. It supports both single-phase and three-phase systems, making it ideal for motors, lighting, transformers, and industrial equipment.
| Parameter | Description |
|---|---|
| Current Type | Select circuit type: • Direct Current (DC): Constant flow from positive to negative pole • Single-phase AC: One live conductor (phase) + neutral • Two-phase AC: Two phase conductors, optionally with neutral • Three-phase AC: Three phase conductors; four-wire system includes neutral |
| Voltage | Electric potential difference between two points. • Single-phase: Enter **Phase-Neutral voltage** • Two-phase / Three-phase: Enter **Phase-Phase voltage** |
| Current | Flow of electric charge through a material, unit: Amperes (A) |
| Power Factor | Ratio of active power to apparent power, indicating efficiency. Value between 0 and 1. Ideal value: 1.0 |
| Apparent Power | Product of RMS voltage and current, representing total power supplied. Unit: Volt-Ampere (VA) |
| Reactive Power | Energy alternately flowing in inductive/capacitive components without conversion to other forms. Unit: VAR (Volt-Ampere Reactive) |
| Resistance | Opposition to DC current flow, unit: Ohm (Ω) |
| Impedance | Total opposition to AC current, including resistance, inductance, and capacitance. Unit: Ohm (Ω) |
The general formula for active power is:
P = V × I × cosφ
Where:
P: Active power (W)
V: Voltage (V)
I: Current (A)
cosφ: Power factor
P = S × cosφ
P = Q / tanφ
P = I² × R
P = V² / R
If voltage is 230V, current is 10A, and power factor is 0.8, then active power is:
P = 230 × 10 × 0.8 = 1840 W
1. Monitor active power regularly to assess equipment efficiency
2. Use data from energy meters to analyze consumption patterns and optimize usage
3. Consider harmonic distortion when dealing with nonlinear loads (e.g., VFDs, LED drivers)
4. Active power is the basis for electricity billing, especially under time-of-use pricing schemes
5. Combine with power factor correction to improve overall energy efficiency
The active power calculator computes real working power in watts(W). It supports DC, single‑phase AC, two‑phase AC and three‑phase AC systems.
Calculations can be done via voltage‑current‑power factor, apparent power, reactive power, resistance or impedance for motors, lighting, transformers and industrial equipment.
Active power does real work for heat or mechanical motion and is used for electricity billing. Apparent power is the total apparent power from voltage‑current multiplication.
Reactive power circulates between inductors and capacitors without doing useful work. Power factor equals the ratio of active power to apparent power.
This calculator assumes ideal sine‑wave conditions and ignores harmonic distortion and line losses. Non‑linear loads such as VFDs and LED drivers introduce harmonics.
For field work, refer to energy‑meter readings and apply power‑factor correction for energy‑efficiency improvement.
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