How Many Amps Is 500 Watts?
500 W is 4.17 A at 120 V DC. At other common voltages — 240 V: 2.08 A. Use the calculator below for any voltage or circuit type.
500 Watts to Amps — DC Reference Chart
| Voltage | Current (DC) | Application |
|---|---|---|
| 12 V | 41.6667 A | 12V automotive / RV / solar |
| 24 V | 20.8333 A | 24V solar / industrial DC |
| 48 V | 10.4167 A | 48V telecom / e-bike |
| 120 V | 4.1667 A | US household standard |
| 240 V | 2.0833 A | US/EU 240V circuit |
| 480 V | 1.0417 A | Industrial 3-phase (per phase) |
Breaker sizing: At 120V, 500W draws 4.17A — a standard 15A breaker is sufficient. At 240V (2.08A), a 15A breaker is also adequate. Per NEC 210.20, size breakers at 125% of continuous load. Always consult a licensed electrician.
In practice: a 500 W halogen work light
Twin-head halogen work lights are typically 500 W per head, so each head pulls 4.17 A at 120 V. Switch both on and you are at 8.3 A — more than half a 15 A circuit consumed before a single tool is plugged in. On a job site this is the practical reason lighting and power tools are kept on separate circuits.
Frequently Asked Questions
How many amps is 500 watts at 120V?
500 watts at 120V DC = 500 ÷ 120 = 4.1667 amps. For AC single-phase with PF 0.8: 500 ÷ (120 × 0.8) = 5.2083 amps. For AC three-phase with PF 0.8 at 120V L-N: 500 ÷ (120 × 0.8 × √3) = 3.0070 amps.
How many amps is 500 watts at 240V?
500 watts at 240V DC = 500 ÷ 240 = 2.0833 amps. For AC single-phase with PF 0.8: 500 ÷ (240 × 0.8) = 2.6042 amps.
What size breaker do I need for 500 watts?
At 120V, 500W draws 4.17A. The NEC requires breakers sized at 125% for continuous loads: 4.17 × 1.25 = 5.21A. The next standard size is a 15A breaker, which is the minimum residential standard and is more than sufficient. At 240V (2.08A), a 15A breaker is also adequate. Always consult a licensed electrician for circuit design.