Watts = Amps × Volts
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Watts (W)
Amps—
Volts—
FormulaW = A × V
⚠ Safety Notice:
All electrical work should be performed by or reviewed by a licensed electrician. This calculator provides estimates for informational purposes only.
⚠️ Single-Phase Only: This calculator is for DC and single-phase AC resistive loads. For three-phase systems, multiply watts by √3 (1.732) × power factor: I = P / (V × 1.732 × PF). For AC motors and inductive loads, actual current is higher than calculated — divide by the power factor (typically 0.7-0.9 for motors).
How to Convert Amps to Watts
Watts measure power — how much energy a device consumes per second. To find watts from amps, multiply amps by volts. This is useful when you know a circuit's current draw and want to understand total power consumption.
Watts = Amps × Volts (W = A × V)
For example, a 20-amp circuit at 120V can supply up to 2,400 watts. Apply the 80% NEC continuous load rule and you get a safe maximum of 1,920 watts on that circuit. Always account for startup surges on motors and compressors.
AC vs DC Power
For DC circuits, the formula is straightforward. For AC circuits, if you have a power factor (PF) less than 1.0, the true watts (real power) = Amps × Volts × Power Factor. Most household appliances list watts directly on the label.