How Many Watts Is 20 Amps?
A 20 A circuit at 120 V carries 2,400 W (1,920 W continuous), and at 240 V carries 4,800 W. Multiply amps × volts (× power factor for AC). Use the calculator below for any voltage.
Real example: a 20 A kitchen small-appliance circuit
20 A circuits (12 AWG copper) feed kitchen small-appliance, bathroom and garage receptacles. At 120 V that is 2,400 W flat, or 1,920 W continuous. On a 240 V circuit a 20 A breaker carries 4,800 W.
20 Amps to Watts — Voltage Reference Chart
| Voltage | Power (PF 1) | Typical use |
|---|---|---|
| 12 V | 240 W | 12V DC / automotive |
| 120 V | 2,400 W | US household standard |
| 208 V | 4,160 W | 208V commercial (L-L) |
| 240 V | 4,800 W | US/EU 240V circuit |
| 480 V | 9,600 W | Industrial 3-phase (L-L) |
Wire & breaker: A 20 A circuit is normally run in 12 AWG copper. Remember the NEC 80% rule for continuous loads (3 hours+): usable power is 2,400 × 0.8 = 1,920 W at 120 V. Background: watts vs amps. Always confirm with a licensed electrician.
Frequently Asked Questions
How many watts is 20 amps at 120V?
At 120V, 20 A delivers 20 × 120 = 2,400 watts (resistive, PF 1). For a continuous load the NEC limits this to 80%: 1,920 W. For AC with a power factor below 1, multiply by PF.
How many watts is 20 amps at 240V?
At 240V, 20 A delivers 20 × 240 = 4,800 watts; the 80% continuous limit is 3,840 W.
How many watts is a 20 amp 120V kitchen circuit?
A 20 A, 120 V circuit delivers 20 × 120 = 2,400 W, limited to 1,920 W for continuous loads. That is why kitchens require at least two 20 A small-appliance circuits — a toaster and a microwave together can exceed one. Convert individual devices with watts to amps.