100 watts to amps

100 watts is 0.83 amps at 120 volts and 0.42 amps at 240 volts, at a power factor of 1.

100 watts to amps at common voltages

100 watts in amps by voltage, power factor 1
Voltage	Amps, A
12 V DC	8.33
24 V DC	4.17
120 V	0.83
240 V	0.42
208 V three phase	0.28
480 V three phase	0.12

100 watts in amps by voltage.

The AC and three-phase rows assume a power factor of 1, as for heaters and incandescent lamps. Motors and electronics draw more current for the same watts.

How to convert 100 watts to amps

Amps = watts ÷ volts: 100 W ÷ 120 V = 0.83 A, and 100 W ÷ 240 V = 0.42 A. On three phase, amps = watts ÷ (1.732 × volts): 100 W ÷ (1.732 × 208 V) = 0.28 A per line. At a power factor of 0.8, 100 W at 120 V draws 1.04 A.

How much of a 15 or 20 amp circuit 100 watts uses

On a 120 V circuit, 100 W (0.83 A) uses 6% of a 15 amp circuit and 4% of a 20 amp circuit. A 100 W load that runs for three hours or more should stay within 80% of the circuit rating: 12 A on a 15 amp circuit and 16 A on a 20 amp circuit. At 0.83 A, a 100 W continuous load needs a 15 amp circuit.

Nearby values

Amps for 100 to 3,000 watts at 120 V and 240 V
Watts, W	120 V, A	240 V, A
100	0.83	0.42
500	4.17	2.08
1,000	8.33	4.17
1,500	12.5	6.25
2,000	16.67	8.33
3,000	25	12.5

Appliances that draw about 100 watts

Watts to amps calculator

Convert

Power

Voltage

Phase

Power factor

1 for heaters and lights; motors and electronics 0.8–0.95

Result

0.83 A

Power: 100 W
Voltage: 120 V
Share of a 15 A circuit at this voltage: 6%

How it is calculated

Amps = 100 ÷ (120) = 0.83