How many amps is 1,800 watts?
Short answer: 1,800 watts draws 15.00 amps at 120 volts and 7.50 amps at 240 volts (amps = watts ÷ volts). From a 12 V battery through an inverter it is about 176 amps. At 120 V it needs a 20 A circuit if it runs for three hours or more.
1,800 watts to amps at every common voltage
| Voltage | Where you find it | Amps |
|---|---|---|
| 120 V | US household outlet | 15.0 A |
| 208 V | Three-phase building supply | 8.65 A |
| 240 V | US large-appliance circuit | 7.50 A |
| 12 V | Car or RV battery | 150.0 A |
| 24 V | 24 V battery bank | 75.0 A |
| 48 V | 48 V battery bank | 37.5 A |
amps = watts ÷ volts 1,800 W ÷ 120 V = 15.00 A 1,800 W ÷ 240 V = 7.50 A
Can a 1,800 W load go on a 15 or 20 amp circuit?
A breaker can carry its full rating, but NEC 210.20(A) limits a continuous load (three hours or more, like a heater left on overnight) to 80% of it.
| Circuit | Full rating (W) | Can it run 1,800 W? |
|---|---|---|
| 15 A, 120 V | 1,800 | Yes, but not for 3 h+ |
| 20 A, 120 V | 2,400 | Yes, even continuous |
| 15 A, 240 V | 3,600 | Yes, even continuous |
| 20 A, 240 V | 4,800 | Yes, even continuous |
| 30 A, 240 V | 7,200 | Yes, even continuous |
Remember that everything else on the same circuit counts. A 1,800 W heater on a bedroom circuit that also feeds a TV and a computer can trip the breaker even when the heater alone would fit.
What uses about 1,800 watts
- The full rating of a 15 A, 120 V circuit (15 × 120)
- Hair dryers at 1,875 W and high-power induction burners at 1,800 W
- Two 900 W appliances on the same kitchen circuit
Running 1,800 W on backup power
From a portable power station's AC outlets, counting 15% inverter loss, if the inverter is rated for at least 1,800 W:
| Power station | Runtime at 1,800 W |
|---|---|
| 1,024 Wh | 29 min |
| 2,048 Wh | 58 min |
| 3,600 Wh | 1.7 h |
On a generator, a resistive 1,800 W load needs about 2,300 running watts to keep the 20% margin; a motor load of the same running watts needs room for its starting surge too. Check your whole list in the generator size calculator.
What 1,800 watts costs to run
At the US average residential price of 18.19¢/kWh (EIA, January–July 2026), 1,800 W costs $0.33 per hour, or about $29.47 a month at three hours a day. State averages run from 12.36¢ to 46.28¢; use the appliance cost calculator with your state.