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Select whether you need power, current, or voltage.
Electrical & Energy Tool
Three-Phase Power Calculator
Calculate real power, apparent power, reactive power, line current, or voltage for a balanced three-phase AC system. Choose line-to-line or line-to-neutral voltage and see every result with the exact formula used.
Power, current, and voltage modes
kW, kVA, and kVAR results
Line and phase voltage support
Input values
Solve a three-phase calculation
Select what you want to calculate. The tool automatically rearranges the balanced three-phase formula and calculates the complete power triangle.
√3 line formulaFor line-to-line voltage
3 × phase formulaFor line-to-neutral voltage
Power trianglekW, kVA, and kVAR
Three solve modesPower, current, or voltage
How it works
Calculate three-phase values in four steps
The calculator uses standard balanced-load relationships and displays the complete electrical result, not only one converted number.
Enter known values
Add the two required electrical quantities and their units.
Add power factor
Use the equipment nameplate or a measured power-factor value.
Review all results
Read kW, kVA, kVAR, phase angle, current, voltage, and formula.
What does a three-phase power calculator do?
A three-phase power calculator connects voltage, current, power factor, real power, apparent power, and reactive power for a balanced AC system. Three-phase supplies deliver power through three alternating waveforms separated by 120 electrical degrees, which allows motors and industrial equipment to receive smoother power than a comparable single-phase supply.
When line-to-line voltage is entered, total real power is based on the square root of three. When line-to-neutral voltage is entered, the equivalent formula uses three times the phase voltage. Both approaches produce the same result when the voltage relationship is correct.
Core three-phase formulas
Real power using line voltage
P = √3 × VLL × I × PFReal power using phase voltage
P = 3 × VLN × I × PFApparent and reactive power
S = P ÷ PF | Q = √(S² − P²)Understanding kW, kVA, and kVAR
Kilowatts (kW) represent real power that performs useful work. Kilovolt-amperes (kVA) represent apparent power carried by the supply. Kilovolt-amperes reactive (kVAR) represent the reactive component associated with magnetic and electric fields. Power factor is the ratio of kW to kVA.
Practical uses
Where three-phase calculations are useful
Use the tool for preliminary electrical estimates, equipment comparisons, and learning. Final installation and protection decisions require verified design data.
Motors and drives
Estimate electrical input current or power for balanced motor and variable-frequency-drive systems.
Industrial machinery
Review power demand for compressors, pumps, conveyors, chillers, and production equipment.
EV charging
Estimate three-phase charging power or current at common commercial supply voltages.
Solar inverters
Compare line current, output power, and apparent power for three-phase inverter systems.
Generators and UPS
Relate kW demand to kVA loading while accounting for the expected power factor.
Electrical education
Explore how voltage basis, current, power factor, and the power triangle interact.
Frequently asked questions
Three-phase power calculator FAQs
Answers to common questions about balanced three-phase voltage, current, power factor, kW, kVA, and kVAR.
What is the formula for three-phase power?
Using line-to-line voltage, real power is P = √3 × V × I × PF. Using line-to-neutral phase voltage, real power is P = 3 × V × I × PF. The result is in watts when voltage is in volts and current is in amperes.
Why is √3 used in a three-phase calculation?
The square-root-of-three factor comes from the 120-degree phase displacement and the relationship between line-to-line and line-to-neutral voltage in a balanced three-phase system.
Should I enter line voltage or phase voltage?
Use line-to-line voltage when reading between two phase conductors. Use line-to-neutral voltage when reading between one phase and neutral. Select the matching option because the formulas use different multipliers.
How do I calculate three-phase current from kW?
Select Current mode, enter real power, voltage, and power factor, then choose the voltage basis. For line voltage, current equals power divided by √3, voltage, and power factor.
What is the difference between kW and kVA?
kW is real power that performs useful work, while kVA is apparent power supplied to the load. They are equal only at a power factor of 1.00. At lower power factor, kVA is greater than kW.
Does the calculator include motor efficiency?
No. The real-power input should represent electrical input power. If you only know mechanical output power, divide that output by motor efficiency before using it as the electrical real-power input.
Can this be used for an unbalanced three-phase load?
Not for an exact result. The standard formulas assume balanced line currents and sinusoidal voltage. For unbalanced loads, measure each phase and use a suitable three-phase power analyser or phase-by-phase calculation.
Electrical safety reminderThis calculator is for estimation and education. Cable sizing, breaker selection, fault protection, voltage-drop checks, and live electrical work should be completed or verified by a qualified electrician or electrical engineer.