How Many Amps Is 300 Watts?

Answer
2.5 A at 120 V · 1.2 A at 240 V

Amps = watts ÷ volts. A 300 W resistive load draws 2.5 A at 120 V and 1.2 A at 240 V. On 120 V, a continuous load this size needs a 15 A breaker.

Free, no sign-upInstant resultsUpdated October 2026
Calculate
Circuit
W
V
A
PF
1.0 for heaters and lights; 0.8–0.9 for motors.
Result
–
How we calculated this

    Printed from sizebench.com/watts-amps-volts-calculator

    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

    More questions like this

    500 W600 W750 W800 W1,000 W1,200 W1,500 W1,800 W2,000 W2,400 W2,500 W3,000 W3,500 W4,000 W4,500 W5,000 W6,000 W7,000 W7,200 W8,000 W9,600 W10,000 W12,000 W15,000 WAll quick answers

    Amps, breaker and wire by voltage

    VoltageCurrentBreaker (continuous)Copper wire
    120 V2.5 A15 A14 AWG
    208 V1.4 A15 A14 AWG
    240 V1.2 A15 A14 AWG
    480 V 3-phase0.36 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 300 watts?

    Yes. A 15 A circuit at 120 V supplies 1,800 W, or 1,440 W for continuous loads, so 300 W fits.

    How many amps is 300 watts at 12 volts?

    25 A at 12 V DC, before inverter losses (about 28 A through a 90% efficient inverter).

    Open the full calculator: Watts, Amps & Volts Calculator →