Easily convert Watts to Amps with our free online calculator. Supports DC, AC Single-Phase, and Three-Phase systems. Includes formulas, reference tables, and electrical guides.
Understanding Watts to Amps Conversion
To calculate electrical current (Amps) from power (Watts), you must know the voltage of the circuit. This calculation is vital for safely sizing circuit breakers and selecting the correct wire gauge to prevent electrical fires.
The Formula
The conversion is based on Watt’s Law, which states that power is the product of current and voltage. To find Amps, we rearrange the formula:
DC Formula:Amps (I) = Watts (W) / Volts (V)
AC Single-Phase Formula:Amps (I) = Watts (W) / (Volts (V) × Power Factor)
AC Three-Phase (Line-to-Line) Formula:Amps (I) = Watts (W) / (√3 × Volts (V) × Power Factor)
Watts to Amps Quick Reference Table (at 120V)
This table assumes a standard 120V AC circuit with a Power Factor of 1.0 (purely resistive load):
| Power (Watts) | Amps (at 120V) | Amps (at 240V) |
|---|---|---|
| 100 W | 0.83 A | 0.42 A |
| 500 W | 4.17 A | 2.08 A |
| 1,000 W | 8.33 A | 4.17 A |
| 1,500 W | 12.50 A | 6.25 A |
| 2,000 W | 16.67 A | 8.33 A |
Key Electrical Definitions
- Watts (Power): The total amount of energy consumed per second.
- Amps (Current): The rate at which electricity flows through a conductor.
- Volts (Potential): The electrical “pressure” that pushes current through the system.
- Power Factor: The ratio of real power used to the apparent power supplied; it ranges from 0 to 1.
Why use this calculator?
Whether you are calculating the current draw for a new microwave or sizing a circuit for industrial machinery, accuracy is critical. Overloading a circuit by miscalculating amperage can trip breakers or, worse, damage electrical components. Our converter ensures you get precise values for any system configuration.