Skip to content

Watts to Amps Calculator

Convert watts to amps — or amps to watts — for DC, single-phase, and three-phase circuits. Set the voltage and power factor, and WattSimple also shows the NEC breaker and copper wire size the current calls for.

Convert

Current

12.5 A

Power in
1,500 W
At voltage
120 V

NEC wire & breaker for this load

Breaker
15 A
Min. copper wire (75°C)
14 AWG

Copper, 75°C terminations, NEC Table 310.16. Real installs may need derating for ambient heat, conduit fill, or voltage drop. Full wire & breaker chart. Always confirm with a licensed electrician + local AHJ.

Frequently asked questions

For a DC or single-phase circuit, amps = watts ÷ volts (divide by power factor too for AC motors and other reactive loads). For three-phase, amps = watts ÷ (1.732 × line voltage × power factor). Example: 1,500 watts at 120 volts single-phase = 12.5 amps.

Ask AI about this

Open an AI assistant with a question grounded in this page.

ChatGPTClaudePerplexityGoogle AIGrok

Related guides

Related tools

Related converters

kW ↔ Amps

Convert kilowatts to amps (or amps to kW) for DC, single-phase, and three-phase circuits, with the matching NEC wire and breaker size.

Open converter

Volts ↔ Watts

Convert volts to watts (or watts to volts) using the current — watts = volts × amps — for DC, single-phase, and three-phase, with the NEC wire and breaker.

Open converter

Watts ↔ kW

Convert watts to kilowatts and back. 1 kW = 1,000 W. Enter watts or kilowatts to see the other instantly.

Open converter

MW ↔ kW

Convert megawatts to kilowatts and watts (or back) — a power-unit conversion. 1 MW = 1,000 kW = 1,000,000 W. For utility, solar, and generator capacity.

Open converter

Sources & standards

This tool's methodology and data follow US standards and authoritative public datasets: