Three Phase Power
Calculator

Inputs

Apparent power (kVA)
34.641016

Results

Apparent power (kVA)
34.641016
Real power (kW)
31.176914
Reactive power (kVAr)
15.099668
Phase voltage (V)
230.940107

Electrical results

Apparent power (kVA)34.641016
Real power (kW)31.176914
Reactive power (kVAr)15.099668
Phase voltage (V)230.940107

formula-map diagram

Apparent power (kVA)
34.641016
Real power (kW)
31.176914
Reactive power (kVAr)
15.099668
Phase voltage (V)
230.940107

Electrical relationship

Formula

P = √3 × VL × IL × cos φ

= 34.641016151378

Note

This is a simplified model: it applies the textbook relationship to the numbers you entered and assumes ideal components, steady-state sinusoidal conditions, balanced loads and copper resistivity of 0.0172 Ω·mm²/m at 20 °C. It ignores component tolerances, temperature drift, skin effect, harmonics, inrush, transformer and battery losses, and it is not a substitute for the wiring code that applies where you are. Have any installation sized and verified by a licensed electrician or engineer.

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Frequently asked questions

What's the formula for three-phase power?+

For a balanced system, P = sqrt(3) x V_line x I_line x power factor (for real power), or P = 3 x V_phase x I_phase x power factor using phase quantities instead of line quantities.

Why does the sqrt(3) factor appear in three-phase calculations?+

It comes from the 120-degree phase relationship between the three voltage waveforms; when you express power in terms of line-to-line voltage rather than line-to-neutral (phase) voltage, that geometric relationship introduces the square root of 3.

What's the difference between line voltage and phase voltage?+

Phase voltage is measured from one line to the neutral point, while line voltage is measured between two of the three lines. In a standard wye (star) connection, line voltage equals phase voltage times sqrt(3).

Why is three-phase power preferred for industrial equipment?+

Three-phase power delivers constant instantaneous power (unlike single-phase, which pulses), allows smaller conductors for the same power delivered, and lets motors start and run more smoothly without extra starting circuitry.

Does the power factor apply the same way in three-phase as single-phase?+

Yes, power factor still represents the ratio of real to apparent power and is included the same way in the formula; it's typically assumed equal across all three phases in a balanced system, which simplifies the calculation.