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. Also try the Voltage Drop Calculator.

Current 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). See also our calculate Resistance Value, Tolerance & Minimum Resistance — Resistor Color Code.

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. You might also find our calculate Recommended Wire Size (AWG), Circular Mils Required & Actual Voltage Drop — Wire Size useful.

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. Check out our calculate Inductance, Inductance (mH) & Inductance (nH) — Coil Inductance as well.