Amps to Watts

Convert current (amps) to power (watts). Select circuit type and input electrical limits.

DC Circuit: P = I × V. Directly multiply amperes by voltage limit.

A
V
Calculated Real Power
1,800
W
= 1,800 W
P(W) = 15A × 120V
Formula

Interactive Electricity Flow Simulator

Watch the flow of electricity (electrons) change speed in real-time based on calculated wattage!

Visual scale relative to appliances

Basic Electrical Circuit schematic

Current (Amps) represents flow of charge, Voltage (Volts) is electrical potential, and Watts is the energy consumed per unit time.

Understanding Amps and Watts

To calculate electrical power in Watts (W) from electrical current in Amperes (A), you must know the circuit's Voltage (V). Amperes measure the volume rate of charge flow, whereas Voltage measures the electromotive potential force pushing those charges. The total work performed (Watts) is the product of current volume and potential pressure.

Whether you are upgrading your home kitchen appliances, sizing a generator backup, or wiring an electrical service panel, calculating the required wattage of your electrical loads is essential to prevent breaker trips.

⚠️ Circuit Breaker Safety Rule

Never load a standard circuit beyond 80% of its maximum rating for continuous loads. For example, a 15A breaker at 120V yields a maximum capacity of 1,800W, meaning your continuous devices should not exceed 1,440W.

How to Convert Amps to Watts

The conversion method depends on your circuit type (DC or AC):

  • Direct Current (DC): P(W) = I(A) × V(V)
  • Single-Phase AC: P(W) = I(A) × V(V) × PF (where PF is the power factor rating of the appliance).
  • Three-Phase AC: P(W) = √3 × I(A) × V(V) × PF (typically used in commercial facilities).

Standard Household Breaker Capacities

Circuit Breaker Size Voltage (AC) Max Wattage Capacity
15 Amp Breaker 120 V 1,800 W
20 Amp Breaker 120 V 2,400 W
30 Amp Breaker 240 V 7,200 W
50 Amp Breaker 240 V 12,000 W

Frequently Asked Questions

Amperes measure electrical current volume, while voltage measures potential force. Power (watts) requires both elements: a high volume of current under high force equals high power.
For standard household inductive appliances (hairdryers, compressors), power factor is roughly 0.8. Pure resistive loads (lightbulbs, heaters) operate at a perfect 1.0 power factor.