Common Appliance Reference (120V)
| Appliance | Watts (W) | Amps @ 120V | Amps @ 240V |
|---|
* Marked appliances are 240V-only — they are never connected to 120V circuits. Actual draw varies by model and load. These are typical values.
How to Convert Watts to Amps
Converting watts to amps is one of the most common electrical calculations for contractors and homeowners. The formula is straightforward: divide the power in watts by the voltage in volts to get the current in amperes.
Note on Power Factor: The formula above applies to purely resistive loads (heaters, incandescent bulbs). For AC circuits with motors or inductive loads (A/C compressors, refrigerators, power tools), the actual current draw is higher: Amps = Watts ÷ (Volts × Power Factor). Typical power factors range from 0.6 to 0.95. When in doubt, use a clamp meter to measure actual amperage or consult the appliance nameplate for the rated amp draw.
For example, a 1,200-watt microwave on a standard 120-volt circuit draws 10 amps (1200 ÷ 120 = 10). Knowing this helps you size circuit breakers, determine if an outlet is overloaded, and plan electrical panel capacity.
Why Voltage Matters
North American household circuits run at 120V for standard outlets and 240V for heavy appliances like dryers, ranges, and EV chargers. A 240-volt appliance drawing the same wattage will pull half the amps of a 120-volt equivalent — which is why high-power appliances use 240V circuits.
When to Use This Calculator
Use this tool when sizing circuit breakers, checking if a circuit is overloaded, calculating generator capacity requirements, or verifying an appliance will work on an existing circuit. Remember that the National Electrical Code (NEC) requires circuit load not to exceed 80% of the breaker rating for continuous loads.