Three-Phase Power Calculator

Calculate three-phase real power, apparent power, reactive power, and line/phase relationships for Wye and Delta configurations.

Results

Visualization

How It Works

Three-phase power is used in commercial and industrial settings because it delivers more power more efficiently than single-phase. The power triangle relates real power (kW), apparent power (kVA), and reactive power (kVAR) through the power factor.

The Formula

P = √3 x VL x IL x PF  |  VA = √3 x VL x IL  |  VAR = √(VA² - W²)

Variables

  • V_L — Line-to-line voltage in volts
  • I_L — Line current in amperes
  • PF — Power factor (ratio of real to apparent power)
  • Wye — V_phase = V_line / sqrt(3), I_phase = I_line
  • Delta — V_phase = V_line, I_phase = I_line / sqrt(3)

Example

480V, 10A, PF=0.85 in Wye: P = 1.732 x 480 x 10 x 0.85 = 7,067W (7.07 kW). Phase voltage = 480/1.732 = 277V. Phase current = 10A.

Tips

  • In Wye systems, the phase voltage is line voltage divided by 1.732 -- this gives you 277V from a 480V system.
  • Delta systems have no neutral wire -- the phase voltage equals the line voltage.
  • Low power factor means you are paying for more current than you are actually using as real power.
  • Power factor correction capacitors can bring PF closer to 1.0 and reduce your electricity bill.
  • Most utility companies charge a penalty if your power factor drops below 0.9.