Three-phase power matrix calculator

Calculate Australian three-phase kVA, kW, kVAr and current cross-check values from entered voltage, current and power factor.

  • Calculator
  • Power conversion
  • Australia
Use the switchboard, load or meter reference.
V
Enter three-phase line-to-line voltage.
A
Enter balanced three-phase line current.
PF
Enter the PF value for the operating point.
S = sqrt(3) x V_LL x I / 1000; P = S x PF; Q = S x sin(arccos(PF)); I_check = P x 1000 / (sqrt(3) x V_LL x PF)
  • Voltage is entered as line-to-line voltage.
  • Current is entered as balanced line current.
  • PF must be above 0 and not greater than 1.
  • The calculator does not assess voltage unbalance, current unbalance, harmonic content or metering uncertainty.
Formula variables
VariableMeaningUnitUse
SApparent powerkVAThree-phase apparent power from line voltage and current.
V_LLLine voltageVEntered line-to-line voltage.
ILine currentAEntered balanced three-phase line current.
PFPower factorratioEntered power factor for the operating point.
PReal powerkWApparent power multiplied by PF.
QReactive powerkVArReactive component from the power triangle.
I_checkCurrent cross-checkACurrent recalculated from kW, voltage and PF.
More

Three-phase power matrix calculator technical guide

Calculate Australian three-phase kVA, kW, kVAr and current cross-check values from entered voltage, current and power factor.

Use this calculator when a three-phase load needs one visible relationship record: line voltage, line current, power factor, apparent power, real power and reactive power. It is useful for Australian switchboard notes, plant load records, estimating checks and handoffs into demand, cable or power-factor workflows.

The calculator is intentionally narrow. It assumes the entered values represent a balanced three-phase operating point and does not check voltage unbalance, current unbalance, harmonic distortion, instrument uncertainty, protection settings or equipment suitability.

Power Matrix Use Cases

Three-phase power matrix use cases
Work situationEntered basisUseful outputOutside the result
Switchboard load noteLine voltage, line current and PFkVA, kW, kVAr and current cross-checkCable size or protection decision
Plant estimateNominal 400 V, current and expected PFPower matrix for an estimating recordMetering confirmation or load balance proof
Metering summaryMeasured current and measured PFConsistent relationship valuesInstrument accuracy or data logging analysis
Demand handoffkW and kVA context from currentValues for demand or tariff worksheetsTariff interpretation
Correction planningReactive component visible beside real powerkVAr context before correction worksheetCapacitor equipment selection

A matrix record is strongest when the voltage, current and PF are all from the same operating condition. Mixing a design current with a measured PF from another period can make the relationship look more precise than it is.

Three-Phase Boundary

Three-phase matrix boundary
Included in this calculatorNot included in this calculator
Line-to-line voltagePhase-by-phase voltage unbalance
Balanced line currentCurrent unbalance or neutral current
Entered PFHarmonic distortion or waveform quality
kVA, kW, kVAr and PF angleCable, protection or transformer selection
Current cross-checkMeter calibration or instrument uncertainty

The boundary matters because the formula is only a relationship between entered values. A real installation may need separate measurement, balancing, protection, harmonic or manufacturer checks before design decisions are made.

Input Checklist

Values to collect before using the matrix
InputStrong basisWeak basis
Matrix referenceSwitchboard, meter, load or estimate recordGeneric note with no traceable load
Line voltageMeasured or documented line-to-line valueAssumed value that does not match the site
Line currentBalanced current basis for the same load conditionOne phase current used as if all phases match
Power factorMeasured, calculated or documented PF for the same periodPF copied from a different load or tariff note
Review contextProject note naming how the matrix will be used nextOutput copied into another worksheet with no source

If each phase has materially different current or voltage, keep a separate load-balancing or unbalance record instead of reducing the condition to one balanced matrix.

Review Workflow

  1. Name the switchboard, load, meter or estimate being represented.
  2. Confirm the line-to-line voltage basis for the Australian project context.
  3. Enter the balanced line current value for the same operating condition.
  4. Enter the power factor value that belongs with that current and voltage.
  5. Read kVA, kW, kVAr, PF angle and current cross-check together.
  6. If PF is very low, check the metering basis and load condition before relying on the reactive result.
  7. Send the output to the next calculator only when the source values and assumptions are recorded.
  8. Use separate records for unbalance, harmonics, cable sizing, protection, correction equipment or tariff interpretation.

The workflow makes the three-phase relationship visible without pretending the matrix is a full electrical design review.

Worked Australian Examples

Three-phase power examples
SituationEntered valuesOutput readingPractical note
400 V plant load400 V, 180 A, PF 0.86124.71 kVA, 107.25 kW and 63.64 kVArKeep the load condition with the result.
Planning record400 V, 95 A, PF 0.90Compact matrix for an early estimateNominal voltage is a worksheet basis only.
Low PF matrix review400 V, 140 A, PF 0.64Matrix is calculated with a PF review noteCheck metering before using the reactive value.

These examples use common Australian three-phase context, but the entered voltage should always match the actual project record.

Related Tools

Use the kVA, kW and power factor calculator when the task is a smaller two-value conversion. Use the reactive power kVAr calculator when the kVAr side of the power triangle needs its own record. Use the power-factor relationship chart when the task is explanation rather than calculation.

Next tool selection
Next questionUse next
Convert kVA, kW and PF without currentkVA, kW and power factor calculator
Derive kVAr from kW and PF or kW and kVAReactive power kVAr calculator
Explain the power trianglePower-factor relationship chart
Review low PF correction needPower factor correction calculator

Stop Points

  • The load is materially unbalanced across phases.
  • Voltage values are phase-to-neutral while the calculator expects line-to-line voltage.
  • Current and PF come from different operating conditions.
  • Harmonics or waveform distortion are material to the decision.
  • The matrix is being used as a cable, protection or equipment selection result.

Export the matrix only with the voltage, current, PF source and intended next use. The result is a relationship record, not a complete design decision.

400 V three-phase load matrix

A switchboard note converts a measured three-phase current into kVA, kW and kVAr values.

Reference
TPM-1
Line voltage
400 V
Current
180 A
Power factor
0.86
  1. Apparent power124.71 kVA
  2. Real power107.25 kW
  3. Reactive power63.64 kVAr
Three-phase power matrix107.25 kW

124.71 kVA and 63.64 kVAr.

The matrix keeps apparent, real and reactive power together so downstream power-factor and tariff checks use the same basis.

  • Line voltage is entered as the three-phase line-to-line voltage.
  • The current is the balanced three-phase line current.
  • The power factor is entered by the user.

Nominal Australian supply context

A planning record uses a 400 V three-phase nominal input for a balanced plant load.

Reference
TPM-2
Line voltage
400 V
Current
95 A
Power factor
0.9
  1. Apparent power65.82 kVA
  2. Real power59.24 kW
  3. Reactive power28.69 kVAr
Three-phase power matrix59.24 kW

65.82 kVA and 28.69 kVAr.

The result gives a compact power triangle record before cable, demand or equipment worksheets are used.

  • The voltage value is a nominal worksheet input.
  • The load is treated as balanced for this calculation.
  • Measured unbalance and harmonics need separate records.

Low PF matrix review

A plant estimate uses a low power factor to decide whether more metering context is needed.

Reference
TPM-3
Line voltage
400 V
Current
140 A
Power factor
0.64
  1. Apparent power96.99 kVA
  2. Real power62.08 kW
  3. Reactive power74.53 kVAr
Three-phase power matrix62.08 kW

96.99 kVA and 74.53 kVAr.

The matrix can be calculated, but low power factor should be checked before relying on the reactive component.

  • The entered PF reflects the operating condition being reviewed.
  • The calculator does not size correction equipment.
  • Reactive power records should be paired with metering context.

Questions

Does this calculator assume balanced three-phase load?

Yes. It uses the balanced three-phase relationship from entered line voltage, line current and PF.

Can I use 400 V as the voltage?

Use 400 V only when it matches the Australian three-phase line-to-line basis for the project record being reviewed.

What does the current cross-check show?

It recalculates current from the calculated kW, entered voltage and PF so the relationship stays visible.

Does this check voltage unbalance?

No. Use a separate voltage-unbalance record when phase voltages are materially different.

Does this size cables or protection?

No. It gives a power relationship record that may feed later cable, protection, demand or equipment checks.