Conversion tool

Watts and Amps Calculator

Enter watts or amps with voltage, phase, and power factor to convert watts to amps or amps to watts while keeping the circuit context with the result.

Convert Watts and Amps

Enter watts or amps, voltage, phase, and power factor to convert watts to amps or amps to watts for DC, single-phase AC, and balanced three-phase AC loads.

Result

Amps

13.33 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

Enter watts or amps with voltage, phase, and power factor to convert watts to amps or amps to watts while keeping the circuit context with the result.

Formula context

Watts to Amps Chart

Watts to amps answer: 1,500 W at 120 V is 12.5 A, 1,500 W at 240 V is 6.3 A, and 9,000 W at 240 V is 37.5 A for a unity-PF single-phase load. Use the calculator when power factor, three-phase voltage, duty cycle, or equipment context must stay with the amp result.

Formula

Single phase: A = W / (V x PF). Balanced three phase: A = W / (1.732 x VLL x PF).

Variables to keep with the result

  • A is current in amperes.
  • W is real load power in watts.
  • V is voltage for DC or single-phase calculations.
  • VLL is line-to-line voltage for balanced three-phase calculations.
  • PF is power factor when applicable.

Formula and variables

For DC and simple single-phase checks, watts to amps is current = watts divided by volts when the load is resistive, and amps to watts is watts = volts x amps. For balanced three-phase AC, current is watts divided by the square root of 3, line-to-line voltage, and power factor. Keep the voltage basis with the result: 120 V branch circuits, 240 V equipment, 208 V panels, 277 V lighting, and 480 V three-phase loads are not interchangeable.

U.S. field workflow

Use this page when a device label, panel note, or load list gives watts but the review needs current. Enter the actual circuit voltage, phase, and PF so the calculator result stays attached to the load basis and does not become a standalone sizing answer.

When to use the full calculator

Use the full power calculator when you need apparent power, reactive power, multiple unknowns, or a complete AC power triangle. Move to the wire, breaker, voltage-drop, or motor calculators when the result will drive conductor sizing, overcurrent protection, voltage-drop review, or motor branch-circuit decisions.

Common Questions

Does this conversion replace a breaker or wire size calculator?
No. It only converts between watts and amps. Conductor sizing and breaker selection require the applicable load type, temperature, terminals, continuous-load rules, and the adopted code.
Why does three-phase use the square root of 3?
Balanced three-phase line power uses the relationship between line voltage, line current, and phase displacement, so the formula includes the square root of 3.
Should I use line-to-line or line-to-neutral voltage?
Use line-to-line voltage for balanced three-phase loads. Use the actual load voltage for DC and single-phase checks.