Power converter

Amps to Watts Calculator

Convert current in amps and voltage to power in watts — DC, AC single-phase, or AC three-phase.

How Amps to Watts works

To calculate watts from amps and volts, you multiply the current by the voltage. This represents the basic power formula: Power (Watts) = Current (Amps) × Voltage (Volts).

For alternating current (AC) circuits, real power is also dependent on the power factor (PF), which accounts for phase shift between voltage and current. In three-phase circuits, a multiplier of √3 (approximately 1.732) is applied to line-to-line voltage.

Formula

1P(W) = I(A) × V(V) (DC)DC

2P(W) = I(A) × V(V) × PF (AC single phase)1Φ

3P(W) = I(A) × V(V) × PF × √3 (AC three phase)3Φ

1 watt = 1 volt × 1 amp (at PF = 1.0).

Amps to Watts conversion table

Reference Table7 rows

Amps to watts at common voltages (DC / resistive, PF = 1.0).
Current (Amps)↕	At 12 V↕	At 120 V↕	At 240 V↕
1 A	12 W	120 W	240 W
5 A	60 W	600 W	1,200 W
10 A	120 W	1,200 W	2,400 W
15 A	180 W	1,800 W	3,600 W
20 A	240 W	2,400 W	4,800 W
30 A	360 W	3,600 W	7,200 W
50 A	600 W	6,000 W	12,000 W

💡 Click any row to auto-fill the calculator aboveClick column headers to sort

FAQ: Amps to Watts

How do you convert amps to watts?

Multiply the current in amps by the voltage in volts. For DC, the formula is Watts = Amps × Volts. For AC, multiply by the power factor. For three-phase AC, multiply by volts × amps × power factor × 1.732.

How many watts is 15 amps at 120 volts?

On a standard household 120 V circuit with a resistive load (such as a heater or light bulb with a power factor of 1.0), 15 amps × 120 volts equals 1,800 watts.

Why do I need voltage to convert amps to watts?

Amps represent current (the volume of electrical flow), while watts represent actual power. Voltage is the electrical pressure. Without knowing the pressure pushing the current, you cannot calculate the total power output.

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