How Many Amps Is 1,800 Watts at 120 V?
15 A
1,800 watts at 120 V draws 15 A: amps = watts ÷ volts. For a load that runs 3 hours or more, the National Electrical Code 80% rule calls for a circuit of 20 A or larger (80% rule).
1,800 watts in amps at different voltages
| Voltage | Current | Circuit (continuous load) |
|---|---|---|
| 120 V | 15 A | 20 A or larger (80% rule) |
| 208 V | 8.65 A | 15 A or larger (80% rule) |
| 240 V | 7.5 A | 15 A or larger (80% rule) |
Adjust the numbers
The calculator below is pre-filled with the numbers above. Change any value to match your project.
- In kilowatts
- 1.8 kW
- Circuit for a continuous load
- 20 A or larger (80% rule)
What you will need
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How it is calculated
For single-phase power, amps = watts ÷ (volts × power factor), and watts = volts × amps × power factor. Resistive loads such as heaters and incandescent bulbs have a power factor of 1; motors are lower.
Circuits that carry a load for 3 hours or more should be loaded to no more than 80% of the breaker rating, a rule from the National Electrical Code. The calculator suggests the smallest standard breaker that meets it.
Open the full watts to amps calculator for other shapes, a worked example and FAQs.