How Many Amps Is 1000 Watts?
1,000 W is 8.33 A at 120 V DC. At other common voltages — 240 V: 4.17 A. Use the calculator below for any voltage or circuit type.
1000 Watts to Amps — DC Reference Chart
| Voltage | Current (DC) | Application |
|---|---|---|
| 12 V | 83.3333 A | 12V automotive / RV / solar |
| 24 V | 41.6667 A | 24V solar / industrial DC |
| 48 V | 20.8333 A | 48V telecom / e-bike |
| 120 V | 8.3333 A | US household standard |
| 240 V | 4.1667 A | US/EU 240V circuit |
| 480 V | 2.0833 A | Industrial 3-phase (per phase) |
Breaker sizing: At 120V, 1000W draws 8.33A. Per NEC 210.20, size breakers at 125% of continuous load: 8.33 × 1.25 = 10.42A. A standard 15A breaker is sufficient. At 240V (4.17A), a 15A breaker is also adequate. Always consult a licensed electrician.
In practice: a 1000 W HPS grow light
The classic 1,000 W high-pressure sodium fixture pulls 8.33 A at 120 V, and closer to 1,100 W once ballast losses are counted. Grow lights run twelve hours a day, so they are unambiguously continuous — budget 10.4 A and accept that one fixture effectively owns a 15 A circuit. Growers running several lights almost always move to 240 V, halving the current for identical output.
Frequently Asked Questions
How many amps is 1000 watts at 120V?
1000 watts at 120V DC = 1000 ÷ 120 = 8.3333 amps. For AC single-phase with PF 0.8: 1000 ÷ (120 × 0.8) = 10.4167 amps.
How many amps is 1000 watts at 240V?
1000 watts at 240V DC = 1000 ÷ 240 = 4.1667 amps. For AC single-phase with PF 0.8: 1000 ÷ (240 × 0.8) = 5.2083 amps.
What size breaker do I need for 1000 watts?
At 120V, 1000W draws 8.33A. The NEC requires breakers sized at 125% for continuous loads: 8.33 × 1.25 = 10.42A. A 15A breaker is sufficient. At 240V (4.17A), a 15A breaker is also adequate.