Conduit Fill Calculator
Check raceway fill percentage, allowed capacity, and whether you need the next conduit size.
Raceway & Conductors
Project Summary
Suggested conduit step-up
Fill percentage
28.5%
Allowed fill
40.0%
Used area
0.152 in^2
Allowed area
0.213 in^2
Recommendation
This conduit size is within the standard fill limit. You still have 0.061 in^2 of allowed area left, which is about 1 more conductors of the same size and insulation.
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Select conduit type, trade size, insulation type, wire size, and conductor count to see fill percentage against standard limits.
Standard Conduit Fill Rules
Fill limits depend on conductor count: one conductor allows 53%, two allow 31%, and three or more allow 40% in common practice. Always verify against your exact code cycle and conductor mix.
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