Conduit fill calculator: how many wires fit in a conduit?
9 wires
12 AWG THHN in 1/2 in EMT · 3/4 in takes 16 · IRC 2021 Table E3904.6(1) · for wires of one size and type
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9 wires
12 AWG THHN in 1/2 in EMT · 3/4 in takes 16 · IRC 2021 Table E3904.6(1)
Source: IRC 2021 Section E3904.6 and Tables E3904.6(1) to (10), Maximum Number of Conductors in conduit and tubing (International Code Council; NEC Annex C), read November 3, 2026. Read the source
A 1/2 inch EMT conduit holds 9 wires of 12 AWG THHN or THWN-2 by IRC 2021 Table E3904.6(1); 3/4 inch EMT holds 16, and 14 AWG fits 12 in 1/2 inch.
A worked example
Seven 10 AWG THHN wires in Schedule 40 PVC needs 3/4 in conduit. 1/2 in Schedule 40 PVC takes 5 wires of 10 AWG THHN and 3/4 in takes 9, by IRC 2021 Table E3904.6(10). In 1/2 in EMT the same wire fits 5 too, so the bore of the tubing, not the wire, decides the size.
How many wires in 3/4 EMT?
22 of 14 AWG, 16 of 12 AWG, 10 of 10 AWG and 6 of 8 AWG THHN or THWN-2, by IRC 2021 Table E3904.6(1). In XHHW the 3/4 in counts are 15, 11 and 8 for 14, 12 and 10 AWG.
How many wires in 1/2 conduit?
In 1/2 in EMT, 12 of 14 AWG, 9 of 12 AWG and 5 of 10 AWG THHN. In 1/2 in Schedule 40 PVC, 11, 8 and 5; in Schedule 80 PVC, 9, 6 and 4, because its wall is thicker and the bore smaller.
How many wires in 3/4 PVC conduit?
Schedule 40: 21 of 14 AWG, 15 of 12 AWG and 9 of 10 AWG THHN (Table E3904.6(10)). Schedule 80: 17, 12 and 7 (Table E3904.6(9)).
What else it is called
Also searched as how many wires in 3/4 conduit, how many wires in 1/2 conduit, how many wires in 3/4 EMT or a conduit fill chart. The count includes every conductor in the conduit, grounds too, and the type letters are the ones printed on the wire jacket.
Wires per conduit size
| THHN or THWN-2 | 1/2 in | 3/4 in | 1 in | 1 1/4 in | 1 1/2 in | 2 in |
|---|---|---|---|---|---|---|
| 1 AWG in EMT | 1 | 1 | 1 | 4 | 5 | 8 |
| 2 AWG in EMT | 1 | 1 | 3 | 5 | 7 | 11 |
| 3 AWG in EMT | 1 | 1 | 3 | 6 | 8 | 13 |
| 4 AWG in EMT | 1 | 2 | 4 | 7 | 10 | 16 |
| 6 AWG in EMT | 2 | 4 | 7 | 12 | 16 | 26 |
| 8 AWG in EMT | 3 | 6 | 9 | 16 | 22 | 36 |
| 10 AWG in EMT | 5 | 10 | 16 | 28 | 38 | 63 |
| 12 AWG in EMT | 9 | 16 | 26 | 45 | 61 | 101 |
| 14 AWG in EMT | 12 | 22 | 35 | 61 | 84 | 138 |
| 1/0 AWG in EMT | 1 | 1 | 1 | 3 | 4 | 7 |
| 2/0 AWG in EMT | 0 | 1 | 1 | 2 | 3 | 6 |
| 3/0 AWG in EMT | 0 | 1 | 1 | 1 | 3 | 5 |
| 4/0 AWG in EMT | 0 | 1 | 1 | 1 | 2 | 4 |
| 14 AWG in PVC Schedule 40 | 11 | 21 | 34 | 60 | 82 | 135 |
| 12 AWG in PVC Schedule 40 | 8 | 15 | 25 | 43 | 59 | 99 |
| 10 AWG in PVC Schedule 40 | 5 | 9 | 15 | 27 | 37 | 62 |
| 8 AWG in PVC Schedule 40 | 3 | 5 | 9 | 16 | 21 | 36 |
| 6 AWG in PVC Schedule 40 | 1 | 4 | 6 | 11 | 15 | 26 |
Maximum number of conductors of one size and type, IRC 2021 Table E3904.6(1), electrical metallic tubing, and Table E3904.6(10), rigid PVC conduit Schedule 40 (NEC Annex C, Tables C.1 and C.10), as printed. The other eight tubing types and the TW, THW, XHHW and RHW columns are in the calculator above.
Where the numbers come from
- IRC 2021 Section E3904.6: “The maximum number of conductors installed in conduit or tubing shall be in accordance with Tables E3904.6(1) through E3904.6(10).” The ten tables are EMT, ENT, FMC, IMC, FNMC-B, FNMC-A, LFMC, RMC, PVC Schedule 80 and PVC Schedule 40, trade sizes 1/2 to 2 in (3/8 in for FNMC), 14 AWG to 4/0. Read November 3, 2026, in the Colorado adoption, and checked row by row the same day against the Utah adoption: identical. IRC 2021 Chapter 39
- TW and THW from 14 to 8 AWG come from the row printed as TW, THHW, THW, THW-2; from 6 AWG up, from the row shared with RHH and RHW without outer covering. Where the published table repeats a size with two different counts or leaves it out (4/0 TW and RHW in FMC, 2/0 and 4/0 THHN in IMC), or prints a count that breaks its row (10 AWG RHW in FMC reads 14 in 1/2 in and 5 in 3/4 in; 8 AWG RHW in FNMC-B reads 1 in 2 in), the page gives no count.
- Minimum size for a number of wires: the smallest trade size of the same conduit whose count is that number or more.
The tables are for wires of one size and one type. Mixed sizes in one conduit need the wire and conduit areas of NEC Chapter 9, Tables 4 and 5, which the IRC does not print, so they are not in this calculator. Neither are data cable or conduit over 2 in.
By Javier Miralles · Last updated . How this site is made.
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