Circuit Breaker Size Calculator — Free Online Calculator
Calculate the correct circuit breaker size for your electrical load. NEC-compliant with continuous and non-continuous load factors.
How to Use This Calculator
Enter the continuous load (running more than 3 hours) and any non-continuous loads on the circuit.
The Formula Explained
NEC 210.20 requires breaker ≥ 125% of continuous load + 100% of non-continuous load. Then round up to the next standard breaker size.