 # Amps to Watts

Amps (A) to Watts (W) calculator and how to calculate

## Amps (A) to Watts (W) calculator

 Current type: DC AC - Single phase AC - Three phase Current in amps: A Voltage in volts: V Watts: W

## Converting Amps to Watts

### Converting DC amps to Watts

The SI unit of power P is Watts (W) while ampere (A) is the SI unit of electric current. To calculate power, in watts, you should multiply the voltage V, in volts (V) by the current I in amps (A).

P(W) = I(A) × V(V)

Therefore:

Watts (W) may be calculated by multiplying volts (V) by amps (A), as follows

Watt = amp × volt

Or

W = A × V

Example

Given that the current through an electrical circuit is 4A and the voltage across the circuit is 110V, calculate its power consumption in watts.

Solution

Power P = Current I × Voltage V

P = 110V × 3A = 440W

### AC single phase Amps to Watts conversion

The actual power P in watts (W) for AC single phase amps is calculated by multiplying the root mean square (RMS) of voltage by the power factor PF and then multiplying the result by the phase current I.

P(W) = PF × I(A) × V(V)

Therefore:

Watts = Volts × the Power factor × amps

watt = PF × amp × volt or W = PF × A × V

Example

Calculate the Power Consumption in watts, given that the phase current is 4A, the RMS voltage is 110v and the power factor is 0.7.

Solution

Power P = power factor x the voltage in volts x current in amps

P = 0.7 × 4A × 110V = 308W

### AC three phase amps to watts conversion

Calculating watts using the line to line voltage

The actual power P in this case, may be calculated by multiplying the phase current I, in amps (A), the power factor PF and the line to line RMS voltage VL-L, which should be in Volts (V). You should then multiply the result with the square root of 3.

P(W) = 3 × PF × I(A) × VL-L(V)

Therefore:

Watts = √3 × PF × Volts × Amps

Example

Work out the power consumption in an electrical system, in watts, given that the phase current in the circuit is 3A, the RMS voltage is 110V and the power factor is 0.8.

Solution

Power P =PF × A × V × √3

P = 3 × 0.8 × 3A × 110V = 457W

Using the line to neutral Voltage to calculate Watts

To calculate power in watts using the line to neutral voltage, the assumption is that the loads in the circuit are balanced. In that case, you calculate the power P by multiplying the power factor PF times the line to neutral RMS VL-O voltage, in Volts (V) and then multiplying the result by 3.

P(W) = 3 × PF × I(A) × VL-0(V)

Therefore:

Watts is equivalent to 3 times the amps (A) multiplied by the power factor (PF) multiplied by the volts (V)

Watt = 3 × PF × amp × volt

or

W = 3 × PF × A × V