Electrical
Amp Calculator
Convert watts to amps for single-phase or three-phase circuits, and check it against a breaker.
Result
Electrical work is life-safety work governed by the NEC or your local code, and must be designed and installed by a licensed electrician. Conductor and overcurrent sizing depends on ambient temperature, conductor bundling, termination ratings, continuous-load rules and more. This is an educational estimate and must never be used as the basis for an installation. Continuous loads must be sized at 125% under the NEC. The suggested breaker ignores conductor ampacity, which must also be checked.
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About this calculator
How many amps is 5,000 watts?
About 20.8 A at 240 V, or 41.7 A at 120 V. Voltage matters enormously: the same power draws half the current at twice the voltage.
What is a continuous load?
One expected to run for three hours or more, such as lighting, EV charging or HVAC. The NEC requires sizing conductors and breakers at 125% of it.
The formula
A = W ÷ (V × PF) single phase; A = W ÷ (V × √3 × PF) three phase
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