NEC Conduit Fill Calculator

Calculate conduit fill percentage and minimum conduit size for a given set of conductors per NEC Chapter 9.

Total number of conductors in the conduit.
Cross-section area including insulation. 12AWG THHN: 8.58mm².
mm²
1=3/4", 2=1", 3=1-1/4", 4=1-1/2", 5=2" (internal area).

Results

Total Conductor Area-mm²
Conduit Internal Area-mm²
Fill Percentage-%
NEC Max Fill-%
Compliance-
References: NEC Chapter 9 Table 1 & Table 5; NFPA 70