Conduit Fill Chart (THHN)

Pick a conduit type and trade size — see the legal count for every conductor size.

Behind the numbers

Counts divide the conduit's internal area (NEC Chapter 9, Table 4) by the THHN/THWN-2 conductor area (Table 5) at the 40% fill limit for three or more conductors. One- and two-conductor pulls use 53% and 31% instead — the conduit fill calculator handles those cases and single lookups.