Amps to Watts Calculator

Convert electric current in Amps (A) to electric power in Watts (W).

How to Convert Amps to Watts

Ampere (A) is the unit of electric current, measuring the flow of electric charge.

Watt (W) is the unit of electric power, measuring the rate of energy transfer.

Calculating Watts from Amps requires knowing the voltage and the type of current (DC or AC).

DC Watts Calculation Formula

For DC circuits, power (in Watts) is equal to the current (in Amps) multiplied by the voltage (in Volts).

P(W) = I(A) × V(V)

AC Watts Calculation Formula

For AC circuits, the Power Factor (PF) must be included to calculate real power.

Single Phase AC

P(W) = I(A) × V(V) × PF

Three Phase AC (Line-to-Line Voltage)

P(W) = √3 × I(A) × VL-L(V) × PF

Three Phase AC (Line-to-Neutral Voltage)

P(W) = 3 × I(A) × VL-N(V) × PF

Typical Power Factor Values

Do not use typical power factor values for accurate calculations.

Appliance / Load Power Factor
Resistive load (Heater, Incandescent light)1.0
LED / Fluorescent lamp0.95
Induction Motor (Full load)0.85
Induction Motor (No load)0.35
2 A120 V240 W 3 A120 V360 W 4 A120 V480 W 5 A120 V600 W 6 A120 V720 W 7 A120 V840 W 8 A120 V960 W 9 A120 V1080 W 10 A120 V1200 W 15 A120 V1800 W 20 A120 V2400 W 25 A120 V3000 W 30 A120 V3600 W 40 A120 V4800 W 50 A120 V6000 W 60 A120 V7200 W 70 A120 V8400 W 80 A120 V9600 W 90 A120 V10800 W 100 A120 V120

Answer:
P = 15 A × 120 V = 1800 Watts

Amps to Watts Conversion Table

The table below shows power values for common current ratings at 120V.

Current (Amps) Voltage (Volts) Power (Watts)
1 A120 V120 W
5 A120 V600 W
10 A120 V1200 W
15 A120 V1800 W
20 A120 V2400 W
30 A120 V3600 W