How Many Watts Is 15 Amps?
A 15 A circuit at 120 V carries 1,800 W (1,440 W continuous), and at 240 V carries 3,600 W. Multiply amps × volts (× power factor for AC). Use the calculator below for any voltage.
Real example: a standard 15 A lighting & receptacle circuit
15 A is the most common residential branch-circuit rating, wired in 14 AWG copper and feeding general lighting and receptacle outlets. At 120 V it can deliver 1,800 W, but the NEC 80% continuous-load rule limits steady draw to 1,440 W. At 240 V a 15 A circuit carries 3,600 W.
15 Amps to Watts — Voltage Reference Chart
| Voltage | Power (PF 1) | Typical use |
|---|---|---|
| 12 V | 180 W | 12V DC / automotive |
| 120 V | 1,800 W | US household standard |
| 208 V | 3,120 W | 208V commercial (L-L) |
| 240 V | 3,600 W | US/EU 240V circuit |
| 480 V | 7,200 W | Industrial 3-phase (L-L) |
Wire & breaker: A 15 A circuit is normally run in 14 AWG copper. Remember the NEC 80% rule for continuous loads (3 hours+): usable power is 1,800 × 0.8 = 1,440 W at 120 V. Background: watts vs amps. Always confirm with a licensed electrician.
Frequently Asked Questions
How many watts is 15 amps at 120V?
At 120V, 15 A delivers 15 × 120 = 1,800 watts (resistive, PF 1). For a continuous load the NEC limits this to 80%: 1,440 W. For AC with a power factor below 1, multiply by PF.
How many watts is 15 amps at 240V?
At 240V, 15 A delivers 15 × 240 = 3,600 watts; the 80% continuous limit is 2,880 W.
How many watts can a 15 amp circuit safely run continuously?
A 15 A, 120 V circuit is rated for 1,800 W momentarily but only 1,440 W continuously (the NEC 80% rule). Keep space heaters, kettles and hair dryers — each ~1,200–1,500 W — one per circuit. Use watts to amps to check any single appliance.