Three Phase Power Calculator
Calculate three-phase power and line current, including the √3 relationship.
About Three Phase Power Calculator
In a balanced star system the line voltage is √3 times the phase voltage, which is where the √3 factor in the power equation comes from. Three-phase delivers three times the power of one phase on only 1.73 times the voltage. Three-phase supply carries far more power per conductor than single phase, which is why all significant industrial loads use it.
Formula
Three Phase Power
P = √3 V_L I_L cos φ; V_phase = V_L ÷ √3
- V_L
- Line-to-line voltage
- V_phase
- Line-to-neutral voltage in a star connection
Worked example
With the default values below, Three Phase Power Calculator returns Real Power of 14.7224. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Line-to-line voltageminimum 1 V
- 400 V
- Line currentminimum 0 A
- 25 A
- Power factoraccepts 0.01–1
- 0.85
Results
- Real Power
- 14.7224 kW
- Apparent Power
- 17.3205 kVA
- Reactive Power
- 9.1241 kVAR
- Phase Voltage
- 230.94 V
- Power per Phase
- 4.9075 kW
Step by step
- 1Values used
- 2Three Phase Power
- 3Real Power= 14.7224 kW
- 4Apparent Power= 17.3205 kVA
- 5Reactive Power= 9.1241 kVAR
- 6Phase Voltage= 230.94 V
- 7Power per Phase= 4.9075 kW
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Three Phase Power calculated?
P = √3 V_L I_L cos φ; V_phase = V_L ÷ √3 In a balanced star system the line voltage is √3 times the phase voltage, which is where the √3 factor in the power equation comes from. Three-phase delivers three times the power of one phase on only 1.73 times the voltage.
Why does Three Phase Power matter?
Three-phase supply carries far more power per conductor than single phase, which is why all significant industrial loads use it.
What values do I need to enter?
This calculator takes 3 inputs: Line-to-line voltage, Line current, Power factor. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.