Watts to Amps Calculator

Convert watts to amps for DC, single phase, or three phase AC circuits. Easy engineering calculator with clear formulas and steps.

Full original guide (expanded)

Watts to Amps Calculator

Convert power (W or kW) to current (amps) for DC, single-phase AC, or three-phase AC circuits. Enter your data and see the formula used and step-by-step solution.

Required for AC only; leave blank for DC

Formulas Used

  • DC: I = P / V
  • AC 1-phase: I = P / (V × PF)
  • AC 3-phase: I = P / (√3 × V × PF)
    where V is line-to-line voltage

Worked Example

Example: What is the current if you have a 1500W single-phase AC load, 120V supply, PF = 0.85?

  • I = 1500 / (120 × 0.85) = 14.71 A

Frequently Asked Questions

Do I need power factor for DC?

No, DC does not use PF. Leave the field blank; it is ignored for DC.

What if I only know apparent power (VA)?

Multiply kVA by PF to get real power, then use the real power in this calculator.

Is the answer always the current the circuit will draw?

The result is the running current. For sizing conductors and breakers, follow local electrical codes as you may need to account for continuous loading, starting (inrush), or ambient conditions.

Tool by Ugo Candido. Last reviewed: 2025.
Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Unit conversion
\[y = x\cdot k\]
y = x * k
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
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Formulas

(Formulas preserved from original page content, if present.)

Version 0.1.0-draft
Citations

Add authoritative sources relevant to this calculator (standards bodies, manuals, official docs).

Changelog
  • 0.1.0-draft — 2026-01-19: Initial draft (review required).