How do you calculate three-phase power?

For balanced three-phase systems: Real power P = √3 × V_LL × I_L × PF (kW). Apparent power S = √3 × V_LL × I_L (kVA). Reactive power Q = √3 × V_LL × I_L × sin(arccos(PF)) (kVAR). The √3 factor (1.732) accounts for the phase relationship between the three phases.

What is the difference between wye and delta connections?

In a wye (star) connection, each load connects between a phase and neutral, giving V_LN = V_LL/√3. In a delta connection, loads connect between phases, so V_LN = V_LL. Line current in delta is √3 times phase current. The calculator handles both configurations.

How do you convert kW to current in a 3-phase system?

I_L = kW × 1000 / (√3 × V_LL × PF). For example, 50 kW at 480V with PF 0.85 gives I_L = 50000 / (1.732 × 480 × 0.85) = 70.7 amps. Use our reverse mode to solve for current from known power.

3-Phase Power Calculator

Calculate kW, kVA, kVAR, and line current for balanced three-phase wye and delta systems. Includes an interactive power triangle.

Line-to-Line Voltage (V_LL)

Line Current (I_L)

Power Factor (PF)

Frequency

Line-to-Line Voltage (V_LL)

Real Power (kW)

Power Factor (PF)

Frequency

How the 3-Phase Power Calculator Works

Calculate power quantities for balanced three-phase systems.

Enter System Voltage

Select from standard voltages (208V–600V) or enter a custom line-to-line voltage. Choose wye or delta connection.

Enter Load Parameters

In forward mode, enter line current and power factor. In reverse mode, enter kW to find the required current.

Read All Quantities

See real power (kW), apparent power (kVA), reactive power (kVAR), and phase voltage. The power triangle visualizes the relationship.

Frequently Asked Questions

Common questions about three-phase power calculations.

Real power P = √3 × V_LL × I_L × PF (watts). Divide by 1000 for kW. Apparent power S = √3 × V_LL × I_L (VA). Reactive power Q = √3 × V_LL × I_L × sin(arccos(PF)) (VAR). The √3 factor is approximately 1.732.

In wye (star), each phase connects to a common neutral point. Phase voltage V_LN = V_LL/√3. In delta, phases connect end-to-end and V_LN = V_LL. Line current in delta is √3 times the phase current. Wye allows both single-phase and three-phase loads from the same supply.

I_L = (kW × 1000) / (√3 × V_LL × PF). Our reverse mode does this automatically. For example, 50 kW at 480V with PF 0.85 gives approximately 70.7 amps per phase.