Circuit Breaker Sizing Calculator
Circuit Breaker Sizing
Determine the correct breaker size for a load.
Formula
Breaker = (Watts / Voltage) / Continuous Factor
Frequently Asked Questions
What is the 80 percent rule?
Continuous loads must not exceed 80 percent of breaker rating.
When do I need a 20-amp breaker?
Use 20-amp breakers for kitchen, bathroom, and laundry circuits.