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LoadCairn / Electrical planning

kW, kVA & Amps Calculator

Convert real power, apparent power, voltage, current, and power factor with the phase assumptions and calculation shown alongside each estimate.

Conversion inputs

Illustrative example · editable

The starting example is 5 kW, 208 V line-to-line, 0.90 PF, and balanced three phase. It calculates about 15.42 A. These example inputs are not a product rating or recommendation.

Choose the value to solve for from the other required values.

Uses F = √3, line-to-line voltage, and line current.

Select which known values the equation will use.

Enter real power for this load and operating point.

Use line-to-line RMS voltage for a balanced three-phase load.

Use a measured or equipment-specified power factor when available.

Planning estimate only

Calculated current

Current updated. The displayed estimate is rounded to two decimal places.

Current · planning only

15.42 A
Calculation details

Selected equation

A = 1,000 × kW ÷ (√3 × VLL × PF)

Live calculation trace

A = 1,000 × 5 kW ÷ (1.732051 × 208 V × 0.9 PF) = 15.42068 A

Assumptions

  • Single-phase calculations use voltage across the load and current through that load. Balanced three-phase calculations use line-to-line voltage and line current, with F = √3.
  • Power factor is treated as the ratio kW ÷ kVA. For sinusoidal voltage and current, displacement power factor is cos φ; distorted waveforms can make total power factor differ from cos φ.
  • The entered voltage, current, power, and power factor describe the same operating point. The calculator does not infer missing equipment data.

Limitations

  • This simplified model does not account for phase imbalance, harmonics, voltage drop, efficiency, transient or motor-start current, or equipment-specific operating conditions.
  • It does not select conductors, protective devices, a transformer, a generator, or a PDU, and it does not establish code compliance or available capacity.
  • Confirm actual load data and installation conditions with equipment documentation and a qualified electrical professional before design or procurement.

Source notes

Schneider Electric Electrical Installation Guide: Definition of reactive power

Defines apparent and active power, relates PF to cos φ for sinusoidal signals, and lists single-phase and three-phase power relationships.

Schneider Electric: Single- and three-phase transformer kVA calculation

Gives single-phase kVA = V × I ÷ 1,000 and three-phase kVA = V × I × √3 ÷ 1,000, with related current calculations.

Planning estimate only. This simplified calculator is for early reference and is not engineering design, equipment selection, a safety determination, code compliance, or a guarantee. Verify the actual load and installation with a qualified electrical professional.