How Many Amps Is 1,800 Watts?

Answer
15.0 A at 120 V · 7.5 A at 240 V

Amps = watts ÷ volts. A 1,800 W resistive load draws 15.0 A at 120 V and 7.5 A at 240 V. On 120 V, a continuous load this size needs a 20 A breaker.

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1.0 for heaters and lights; 0.8–0.9 for motors.
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    For estimating and educational purposes only. Results are approximate and are not a substitute for a licensed professional, the manufacturer's instructions or your local code. Disclaimer

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    Amps, breaker and wire by voltage

    VoltageCurrentBreaker (continuous)Copper wire
    120 V15.0 A20 A12 AWG
    208 V8.7 A15 A14 AWG
    240 V7.5 A15 A14 AWG
    480 V 3-phase2.17 A––

    Breaker sized at 125% for continuous loads (NEC 210.20). Motors and electronics draw more current than watts ÷ volts because of power factor.

    Frequently asked questions

    Can a 15 amp circuit handle 1,800 watts?

    Only for short, non-continuous use. A 15 A circuit supplies up to 1,800 W, but continuous loads should stay under 1,440 W; a 20 A circuit is the safer choice.

    How many amps is 1,800 watts at 12 volts?

    150 A at 12 V DC, before inverter losses (about 167 A through a 90% efficient inverter).

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