How Many Watts Is 100 Amps?

Answer
12,000 W at 120 V · 24,000 W at 240 V

Watts = amps × volts. 100 A at 120 V = 12,000 W and 100 A at 240 V = 24,000 W. A 100 A breaker should carry at most 80% of that for continuous loads: 9,600 W at 120 V.

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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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    100 amps in watts by voltage

    VoltageWattsContinuous (80%)
    12 V1,200 W960 W
    120 V12,000 W9,600 W
    208 V20,800 W16,640 W
    240 V24,000 W19,200 W
    480 V 3-phase83,138 W66,511 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 100 amp breaker handle?

    12,000 W at 120 V or 24,000 W at 240 V, and 80% of that for continuous loads.

    How many watts is 100 amps at 12 volts?

    1,200 W.

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