What it calculates
Estimate a planning breaker size from load and continuous-load factor.
Breaker Load Planning Calculator
Estimate a planning breaker size from load and a continuous-load factor.
Planning and estimating aid only. Verify project requirements, manufacturer instructions, adopted codes, permits, and field conditions before performing regulated work.
Electrical planning
How to Use This Calculator
Use the field units shown below, then compare your result with the worked example. Use the actual load basis required for the equipment and circuit, and have the final protection and conductors checked together.
How the calculation works
The entered load is multiplied by the selected continuous-load planning factor, then compared with common breaker sizes.
What the result means
This is a planning result only; breaker size must coordinate with conductor ampacity, equipment requirements and code.
See how the load factor changes the planning result
With an entered load of 16 amps and a selected factor of 1.25, the arithmetic basis is 16 × 1.25 = 20 amps. The tool then finds the first entry in its stored standard-size list at or above that value.
Contractor tip: Use the actual load basis required for the equipment and circuit, and have the final protection and conductors checked together. Do not treat rounding up to a listed breaker as installation approval.
Verify the final quantity
The factor and standard-size list are a simplified model. The result does not verify equipment requirements, conductor ampacity, terminal ratings, starting current, circuit type or local requirements.
Good practice: Compare the calculated quantity with plans, specifications, product packaging and current field conditions before purchasing material.