Circuit Breaker Calculator
Find the right circuit breaker size for any load.
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How It Works
Find the right circuit breaker size for any load. Enter your values and press Calculate for instant results with a full formula breakdown.
Formula
Breaker = Amps x 1.25Quick Reference
Common calculations — results you can verify instantly.
1500W at 120V
1500/120=12.5A×1.25
15A or 20A breaker
3000W at 240V
3000/240=12.5A×1.25
15A or 20A breaker
NEC rule
Continuous load
125% of load current
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