Commercial AC formula

kW and Amps Calculator

Convert kW or amps with voltage, phase, and power factor; for example, 15 kW at 480 V three-phase and 0.90 PF is about 20.1 A.

Convert kW and Amps

Convert kW or amps for commercial AC loads. A 15 kW balanced three-phase load at 480 V and 0.90 PF is about 20.1 A; keep voltage, phase, and PF with the result.

Result

Amps

20.05 A

Result notes. Keep inputs, assumptions, and result together before using this value in project records.

Keep the entered values, assumptions, and result together when adding this calculation to job notes or submittal records. Final installation choices should align with the applicable code edition, equipment listing, manufacturer instructions, local amendments, and AHJ requirements.

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Formula and field context

Convert kW or amps with voltage, phase, and power factor; for example, 15 kW at 480 V three-phase and 0.90 PF is about 20.1 A.

Formula context

Single Phase vs Three Phase Chart

Single-phase and three-phase are not just different voltages; they are different calculation contexts. Single-phase formulas use one voltage and one current path. Balanced three-phase formulas use line-to-line voltage, line current, and the 1.732 multiplier. Split-phase 120/240 V services can have both 120 V line-to-neutral loads and 240 V line-to-line loads on the same service.

Formula

Single phase: P = V x I x PF. Balanced three phase: P = 1.732 x VLL x I x PF.

Variables to keep with the result

  • P is real power in watts.
  • V is the voltage across the single-phase load.
  • VLL is line-to-line voltage for balanced three-phase loads.
  • I is line current.
  • PF is power factor.

Formula and variables

For single-phase AC, amps equals kW times 1,000 divided by volts and power factor. For balanced three-phase AC, amps equals kW times 1,000 divided by the square root of 3, line-to-line voltage, and power factor. Keep the voltage basis, phase, and power factor with every result because each one changes the current.

U.S. field workflow

Use this page when a schedule gives real power but the field note, panel schedule, or load review needs current. For example, a 15 kW balanced three-phase load at 480 V and 0.90 PF is about 20.1 A. Run the calculator with the actual voltage, phase, and PF from the equipment so the result stays tied to the installation basis.

When to use the full calculator

This worksheet covers the kW and current relationship. The full power calculator adds apparent power or reactive power, while wire, breaker, motor, transformer, and voltage-drop calculators handle sizing or code decisions tied to the current result.

Common Questions

Why is kW-to-amps separate from watts-to-amps?
The formula is related, but kW-to-amps is usually a commercial AC task where phase and power factor matter. For example, 15 kW at 480 V three-phase and 0.90 PF is about 20.1 A.
Can I use this for three-phase motors?
It can support a formula estimate from kW, voltage, efficiency assumptions, and power factor. The motor calculator is the better fit when NEC full-load current or motor branch-circuit rules matter.
Does power factor always need to be entered?
For real AC power in kW, yes. If you only have kVA, use the kVA and amps calculator instead.