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Calculator Answers

Watts to Amps Calculator

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A watts to amps calculator computes the electrical current flow rate in amperes based on the total power consumption in watts and the circuit voltage. By dividing power by voltage (and adjusting for power factor in single-phase and three-phase AC systems), it provides the exact current load. This calculation is crucial for determining fuse ratings, selecting conductor wire sizes, and planning appliance installations.

Convert electric power in watts to electric current in amperes. Supports DC, AC single-phase, and AC three-phase circuits.

Quick Answer

Convert electric power in watts to current in amperes. Enter the wattage, voltage, and phase system to compute amps.

Current Type

Formula Used

Amps = Watts / Volts = 1200 / 120

Watts to Amps

Current (Amperage)

10 A

At 120V (DC)

Power1200 W
Voltage120 V
Current10 A

This calculator converts electric power in watts to electric current in amperes. For AC circuits, it adjusts for the phase configuration and power factor (PF), which represents the phase offset between current and voltage.

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How it works

Electric Power Formulas

The formulas used to convert watts (W) to amperes (A) depend on the type of electrical system:

Direct Current (DC)

Amps = Watts / Volts

Alternating Current (AC) Single-Phase

Amps = Watts / (Power Factor × Volts)

Alternating Current (AC) Three-Phase

Amps = Watts / (1.732 × Power Factor × Volts)

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Frequently asked questions

To convert watts to amps, divide the power in watts by the voltage in volts. For direct current (DC) circuits, the formula is A = W / V. For alternating current (AC) circuits, you must also factor in the power factor: A = W / (PF × V) for single-phase systems.

For three-phase AC circuits, the formula is: Amps = Watts / (1.732 × PF × Volts), where 1.732 is the square root of 3, PF is the power factor, and Volts is the line-to-line voltage.

In AC circuits, voltage and current waves can be out of phase. The power factor is a decimal between 0 and 1 representing the ratio of real power (watts) to apparent power (volt-amperes). A higher power factor means more efficient power delivery.

Purely resistive loads like heaters and light bulbs have a power factor of 1.0. Inductive loads like electric motors, refrigerators, and air conditioners typically have a power factor ranging from 0.7 to 0.9.