Watts to Amps Chart

Watts to amps lookup: 1,500 W at 120 V = 12.5 A, 1,500 W at 240 V = 6.3 A, and 9 kW at 240 V = 37.5 A; use the calculator when voltage, phase, PF, or duty basis must stay with the result.

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Quick reference table

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.

Unity power-factor current from common watt loads

Unity power-factor current from common watt loads
Load watts	120 V 1-phase	208 V 1-phase	240 V 1-phase	480 V 3-phase
750 W	6.3 A	3.6 A	3.1 A	0.9 A
1,500 W	12.5 A	7.2 A	6.3 A	1.8 A
3,000 W	25.0 A	14.4 A	12.5 A	3.6 A
4,500 W	37.5 A	21.6 A	18.8 A	5.4 A
9,000 W	75.0 A	43.3 A	37.5 A	10.8 A

Watts-to-amps chart to calculator handoff

Watts-to-amps chart to calculator handoff
Search or worksheet need	Use this chart for	Open the calculator when
Watts to amps chart	Screening current from a listed watt value at a common voltage	Voltage, phase, PF, and load basis must be saved with the result
1500 watts to amps	Checking a common resistive or appliance-load estimate	The label voltage, duty cycle, or receptacle context changes the next step
Three-phase watts to amps	Separating line-to-line voltage from single-phase voltage rows	A balanced three-phase load and PF need one calculated current
Watts, VA, or kVA label	Deciding whether the label is real power or apparent power	The equipment label is VA/kVA or the task is transformer, UPS, or generator current

Before using the amp result for a circuit decision

Before using the amp result for a circuit decision
Watt source	Confirm first	Next calculator context
Portable appliance label	Voltage and duty cycle	Receptacle or branch-load review
Lighting layout total	Driver input watts and control zones	Lighting circuit or energy calculator
Space-heating load	Continuous operating assumption	Branch-circuit and load schedule review
Motor or compressor watts	PF, efficiency, and nameplate FLA	Motor-current calculator

Formula basis

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

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.

Worked examples

Checking a countertop appliance labelA 1,500 W appliance at 120 V draws about 12.5 A before duty-cycle or receptacle context is reviewed.

Reviewing a heater scheduleA 9 kW heater at 240 V draws about 37.5 A for a unity-PF single-phase load; use the calculator when load type or continuous-operation assumptions matter.

Assumptions. Balanced load and line-to-line voltage assumptions behind this chart.

The table assumes unity power factor and rounds current to one decimal place.
The chart does not apply demand factors, circuit rating rules, receptacle configuration limits, or manufacturer instructions.
Three-phase rows assume balanced loads and line-to-line voltage.

Code and standard notes. Planning limits that should be checked before final equipment selection.

Use load type, nameplate data, duty cycle, equipment listing, adopted NEC requirements, and AHJ expectations before selecting conductors or overcurrent devices.

How to use this chart

1Start with the watt labelUse the wattage from a nameplate, submittal, lighting schedule, heater schedule, or appliance label and keep the source visible.

2Choose the served voltageSelect the voltage actually feeding the load. A 120 V plug load, 208 V equipment load, and 240 V heater cannot share the same amp row.

3Decide whether PF appliesFor resistance heat the unity-PF row may be close, while motors and electronic power supplies need PF or manufacturer input data.

4Use the amp result as a handoffCarry the current into the calculator when the next decision involves circuit loading, conductor sizing, energy use, or documentation.

Worksheet checklist. Record source basis, review gaps, and assumptions before using the chart result.

Record wattage basisMark whether watts are measured input, maximum nameplate input, design load, demand estimate, or a combined schedule total.
Add voltage and connectionWrite the voltage and whether the equipment is line-to-neutral, line-to-line, single-phase, or three-phase before using the current.
Flag what the chart excludesNote any continuous-load, demand, startup, derating, or manufacturer instruction that needs a separate review.

Common mistakes to avoid. Review these before turning chart current into an equipment decision.

Using a watt-to-amp estimate as a finished breaker size without checking the equipment and code context.
Using 120 V for equipment that is actually connected at 208 V, 240 V, or 480 V.
Ignoring low power factor and underestimating current for motors, compressors, and electronic loads.

Frequently asked questions

These answers explain how to use the chart without turning a quick reference into a final design decision.

Can this chart choose a breaker?

No. For example, 1,500 W at 120 V is about 12.5 A, but breaker and conductor decisions still need load type, continuous-load treatment, equipment instructions, and the adopted code path.

Why does a 240 V load use fewer amps than a 120 V load?

For the same wattage, higher voltage carries the load with less current. That is why voltage must match the equipment connection before comparing amp values.

What if the equipment label gives VA instead of watts?

Use an apparent-power or kVA path when the label is in VA. Watts describe real power; VA describes apparent power and can produce a different current basis.

When should I open the power calculator from this chart?

Open the calculator when the amp result must include voltage, phase, PF, load type, or a recordable basis for the next circuit or energy review.