Watts to Amps Calculator

Electric power in watts (W) to electric current in amps (A) calculator.

A
mA

Amps to watts calculator ►

* Use e for scientific notation. E.g: 5e3, 4e-8, 1.45e12

Watt

Watt (W) is a unit of power. Power is the rate of energy usage per time unit. One watt (W) is equal to one joule (J) per second (S).

Ampere

Ampere (A) is a unit of electric current. Electric current is the rate of electric charge flow per time unit. One ampere (A) is equal to one coulomb (Q) per second (s).

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

 

Watts to amps calculation ►

 

See also

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