Watts To Amps

Watts to Amps Calculator

Watts: Voltage: Select Phase:

DC watts to amps calculation

The current I in amps (A) is equal to the power P in watts (W), divided by the voltage V in volts (V):

I(A) =

P(W)V(V)

Example

P = 200W, V = 40V

I =

200W40V

= 5A

AC single phase watts to amps calculation

The phase current I in amps (A) is equal to the power P in watts (W), divided by the power factor PF times the RMS voltage V in volts (V):

I(A) =

P(W)PF × V(V)

The power factor of resistive impedance load is equal to 1.

Example

P = 2000W, V = 110V, PF = 0.8

I =

2000W0.8×110V

= 22.72727A

AC three phase watts to amps calculation

Calculation with line to line voltage

The phase current I in amps (A) is equal to the power P in watts (W), divided by square root of 3 times the power factor PF times the line to line RMS voltage VL-L in volts (V):

I(A) =

P(W)√3 × PF × VL-L(V)

The power factor of resistive impedance load is equal to 1.

Calculation with line to neutral voltage

The phase current I in amps (A) is equal to the power P in watts (W), divided by 3 times the power factor PF times the line to neutral RMS voltage VL-N in volts (V):

I(A) =

P(W)3 × PF × VL-N(V)

The power factor of resistive impedance load is equal to 1.

Typical power factor values

Do not use typical power factor values for accurate calculations.

Device	Typical power factor
Resistive load	1
Fluorescent lamp	0.95
Incandescent lamp	1
Induction motor full load	0.85
Induction motor no load	0.35
Resistive oven	1
Synchronous motor	0.9

Watts to amps table (120V)

Power (W)	Voltage (V)	Current (A)
10 watts	120 volts	0.0833 amps
20 watts	120 volts	0.167 amps
30 watts	120 volts	0.250 amps
40 watts	120 volts	0.333 amps
50 watts	120 volts	0.417 amps
60 watts	120 volts	0.500 amps
70 watts	120 volts	0.583 amps
80 watts	120 volts	0.667 amps
90 watts	120 volts	0.750 amps
100 watts	120 volts	0.833 amps
200 watts	120 volts	1.667 amps
300 watts	120 volts	2.500 amps
400 watts	120 volts	3.333 amps
500 watts	120 volts	4.167 amps
600 watts	120 volts	5.000 amps
700 watts	120 volts	5.833 amps
800 watts	120 volts	6.666 amps
900 watts	120 volts	7.500 amps
1000 watts	120 volts	8.333 amps