How Many Watts Is 30 Amps?

Answer
3,600 W at 120 V · 7,200 W at 240 V

Watts = amps × volts. 30 A at 120 V = 3,600 W and 30 A at 240 V = 7,200 W. A 30 A breaker should carry at most 80% of that for continuous loads: 2,880 W at 120 V.

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

    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

    10 A15 A20 A40 A50 A60 A100 AAll quick answers

    30 amps in watts by voltage

    VoltageWattsContinuous (80%)
    12 V360 W288 W
    120 V3,600 W2,880 W
    208 V6,240 W4,992 W
    240 V7,200 W5,760 W
    480 V 3-phase24,942 W19,953 W

    For motors and electronics, multiply by the power factor (typically 0.8–0.95) to get real watts.

    Frequently asked questions

    How many watts can a 30 amp breaker handle?

    3,600 W at 120 V or 7,200 W at 240 V, and 80% of that for continuous loads.

    How many watts is 30 amps at 12 volts?

    360 W.

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