Conversion tool

Watts and Amps Calculator

Convert watts to amps or amps to watts from voltage, phase, and power factor; 1,440 W at 120 V equals 12 A.

Convert Watts and Amps

Convert current and real power for DC, single-phase AC, and balanced three-phase AC loads: 1,440 W at 120 V gives 12 A, and 15,000 W at 480 V 3-phase with 0.90 PF gives about 20.1 A.

Result

Amps

13.33 A

Result notes

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.

Formula and field context

Convert watts to amps or amps to watts from voltage, phase, and power factor; 1,440 W at 120 V equals 12 A.

Formula context

Watts to Amps Chart

Watts-to-amps is the load-planning direction: start with a watt rating and estimate current. 1,500 W at 120 V draws about 12.5 A, while the same wattage at 240 V draws about 6.3 A. For AC equipment with power factor below 1.0, current rises above the simple unity-PF 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, current is watts divided by volts when the load is resistive. 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 example

A 1,440 W load on a 120 V branch circuit draws 12 A when the power factor is 1. A 15,000 W balanced three-phase load at 480 V and 0.90 power factor draws about 20.1 A. Those are formula results for planning and nameplate review, not conductor or breaker approval.

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.