Three-phase systems

3-Phase Amps to Watts Calculator

W = √3 × A × V × PF

3 Phase Amps to Watts Calculator

Select Line-to-Line or Line-to-Neutral to calculate 3-phase power.

Live Result
Formula-backed — instant professional result
CALCULATED POWER
0 W
Also equals 0 kW
Formula used W = √3 × A × V × PF The primary result is shown in W using the formula displayed above. 10A × 480V × 0.9 × 1.732 = 7478W

This calculator is an educational planning estimate. Verify safety-critical work with equipment nameplate data, local electrical code, and a qualified professional.

Convert 3-phase amps to watts with W = 1.732 × A × V × PF. Enter amps, line voltage, and power factor. Includes load chart.

Three-phase amps to watts

Three-phase line-to-line model

Convert 3-phase amps to watts with W = 1.732 × A × V × PF. Enter amps, line voltage, and power factor. Includes load chart.

400V 3-phase formula-first page-specific visual

3-Phase Amps to Watts Calculator — Industrial Power | Ampstowatt Guide

Three-phase power path

Balanced line-to-line power using the 1.732 multiplier

Three-phase pages need line-to-line voltage clarity, so the diagram shows L1, L2, L3 feeding a balanced load.

Formula Watts = 1.732 x Amps x Volts x PF
3-Phase Amps to Watts Calculator — Industrial Power | Ampstowatt technical circuit diagram A premium electrical diagram showing the main values and conversion flow for 3-Phase Amps to Watts Calculator — Industrial Power | Ampstowatt. L1 L2 L3 400 V L-L 1.732 x A x V x PF Balanced load
3-Phase Amps to Watts Calculator — Industrial Power | Ampstowatt Three-phase power path with real formula values and planning checkpoints.

Quick answer

Use this calculator for balanced three-phase loads using line-to-line voltage.

Three-phase power uses the square-root-of-three multiplier when voltage is measured line to line. Motors and industrial loads also need realistic power factor.

Watts = 1.732 x Amps x Volts x PF

Inputs to check before calculating

  • Use line-to-line voltage unless the calculator is set to line-to-neutral.
  • Enter running current from measured values or equipment nameplate.
  • Use motor or equipment PF instead of assuming 1.00.
  • Check whether the load is balanced across phases.

Example: 10 amps at 400 volts

At 400 volts, 10 amps equals 4,000 watts before AC power-factor adjustments. Formula: 10 A x 400 V = 4,000 W.

Best use cases

  • Line-to-line voltage model
  • Motor and industrial loads
  • Real power and kW output
  • three-phase AC load planning with clear unit labels.

Common mistake to avoid

Do not mix line-to-line and line-to-neutral voltage in the same formula.

How to use the result

Use the calculated watts or kW for load planning, generator sizing, and panel capacity checks.

Accuracy and safety note

Calculator output is a planning estimate. Final breaker sizing, wire gauge, derating, voltage-drop limits, equipment protection, and code compliance should be verified with manufacturer documentation and a qualified electrician or engineer.

For the broad formula, reference table, and breaker planning context, start with the main Amps to Watts Calculator.

Related Amps to Watts Calculators

Start with the main conversion tool

Move between AC, DC, phase-specific, formula, chart, and reverse conversion pages without using redirected URLs.Amps to Watts Calculator

Methodology, Review Notes, and Sources

How this calculator works

The calculator applies Watt's law for DC and resistive loads, then adds power factor for AC loads and the 1.732 multiplier for balanced three-phase line-to-line calculations.

  • DC and resistive loads: W = A x V
  • Single-phase AC: W = A x V x PF
  • Three-phase AC: W = 1.732 x A x V x PF

Editorial review

Last reviewed: June 26, 2026. Ampstowatt.com is built around the amps to watts conversion — our core specialty. Content is maintained by the Ampstowatt editorial team and checked for formula consistency, unit labels, calculator behavior, and safety wording.

The page is an educational planning reference, not a licensed electrical design or inspection service.

Reference sources

FAQ

3 Phase FAQ

Fast answers before you use the calculator or compare formulas.

3P What is the three-phase amps to watts formula?

For balanced three-phase loads using line-to-line voltage: Watts = √3 × Amps × Volts × Power Factor (√3 ≈ 1.732). For line-to-neutral voltage: Watts = 3 × Amps × Volts × PF. The √3 factor accounts for the 120° phase offset between the three power lines.

√3 What does √3 (1.732) mean in three-phase power?

The √3 factor is a mathematical constant that relates line-to-line voltage to phase voltage in a balanced three-phase system. Line-to-line voltage is √3 times higher than line-to-neutral voltage. When calculating power from line-to-line measurements, √3 corrects the formula to give the total power across all three phases.

PF How do I find the power factor of a three-phase motor?

Check the motor nameplate — it typically lists PF or cos(φ) at full load. Common values: small motors (1–5 HP) = 0.75–0.85, medium motors (5–50 HP) = 0.82–0.90, large motors (50+ HP) = 0.85–0.92. At partial load, PF drops significantly. You can also measure PF with a three-phase power analyzer.

V What is the difference between line-to-line and line-to-neutral voltage?

Line-to-line (L-L) voltage is measured between any two of the three phase conductors. Line-to-neutral (L-N) is measured from one phase to the neutral or star point. Common L-L values: 208V, 400V, 480V. L-N is L-L ÷ √3: 120V, 230V, 277V respectively. Most three-phase motors and industrial equipment use L-L voltage.

HP How many amps does a 10 HP three-phase motor draw?

A 10 HP three-phase motor at 480V with PF 0.85 and 90% efficiency draws approximately 10.3 amps per phase. Formula: 10 HP × 746W/HP = 7,460W. Amps = 7,460 ÷ (1.732 × 480 × 0.85) = 10.6A. NEC Table 430.250 lists 14A for 460V, 10 HP motors as a conservative reference.

UNB Can I use this calculator for unbalanced three-phase loads?

This calculator assumes balanced three-phase loads (equal current on all three phases). For unbalanced loads, calculate each phase separately as a single-phase circuit and sum the results. Severely unbalanced loads can cause neutral current issues and require individual phase analysis.