Watts to Amps Calculator

Enter your power in watts and voltage in volts to find the current in amps. Select your current type (DC, AC single-phase, or AC three-phase) and adjust the power factor for AC circuits. The Watts to Amps Calculator returns current in amps and milliamps using the correct formula for your circuit type.

W
V

Only applies to AC circuits. Typical value: 0.8. Enter 1 for resistive loads.

Only applies to AC three-phase circuits.

Results

Current

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Current (Milliamps)

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Formula Used

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Results Table

Frequently Asked Questions

What is the formula to convert watts to amps?

For DC circuits: Amps = Watts ÷ Volts. For AC single-phase: Amps = Watts ÷ (Power Factor × Volts). For AC three-phase (line-to-line): Amps = Watts ÷ (√3 × Power Factor × Volts). For AC three-phase (line-to-neutral): Amps = Watts ÷ (3 × Power Factor × Volts).

How many amps is 1000 watts at 120 volts?

For a DC or purely resistive AC circuit: 1000W ÷ 120V = 8.33 amps. For an AC circuit with a power factor of 0.8: 1000W ÷ (0.8 × 120V) = 10.42 amps.

How many amps is 1000 watts at 240 volts?

For a DC or purely resistive AC circuit: 1000W ÷ 240V = 4.17 amps. With a power factor of 0.8: 1000W ÷ (0.8 × 240V) = 5.21 amps.

What is power factor and why does it matter?

Power factor (PF) is a number between 0 and 1 that represents how efficiently electrical power is used in an AC circuit. A PF of 1 means all supplied power is used as real work (resistive loads like heaters). Motors and other inductive loads typically have a PF of 0.7–0.9, meaning more current is drawn than a purely resistive load of the same wattage.

What are amps, volts, and watts?

Amps (amperes) measure the rate of electric current flow — think of it as how much water flows through a pipe. Volts measure the electrical pressure driving that current — like water pressure. Watts measure electrical power, which is the product of current and voltage (W = A × V).

What is the difference between AC and DC power?

DC (Direct Current) flows in one constant direction, as from a battery. AC (Alternating Current) reverses direction periodically and is what comes from standard wall outlets. AC power calculations for reactive loads require a power factor, while DC calculations do not.

How many amps is 1500 watts at 120 volts?

For a DC or resistive AC circuit: 1500W ÷ 120V = 12.5 amps. With a typical AC power factor of 0.8: 1500W ÷ (0.8 × 120V) = 15.63 amps. This is close to the 15-amp limit of a standard US household circuit.

What is the difference between line-to-line and line-to-neutral voltage in three-phase systems?

In a three-phase system, line-to-line voltage is measured between any two of the three phase conductors, while line-to-neutral voltage is measured between one phase conductor and the neutral. Line-to-line voltage is approximately 1.732 (√3) times the line-to-neutral voltage. The formulas for converting watts to amps differ depending on which voltage reference you use.

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