How many 12 AWG wires fit in 1/2 inch EMT?

Using nominal THHN outside diameters and the 40% fill rule, 9 12 AWG conductors fit in 1/2 inch EMT. Every conductor counts, including the neutral and the equipment grounding conductor.

What is the maximum fill percentage for EMT?

40% of the internal cross-sectional area for three or more conductors, 31% for exactly two and 53% for a single conductor. Nipples 24 inches or shorter are permitted at 60%.

What size EMT do I need for three 10 AWG conductors?

Three 10 AWG THHN conductors need at least 1/2 inch EMT at 40% fill. Add a fourth conductor and re-check, because the count changes the usable area.

Does the ground wire count toward conduit fill?

Yes. Fill counts every conductor in the raceway. Grounds are excluded only from the ampacity adjustment count for current-carrying conductors, never from fill.

Where do these EMT numbers come from?

Internal diameters are published product dimensions from the relevant ANSI/UL/ASTM product standards. Area is computed as pi times radius squared, and the conductor count is the largest whole number that fits inside the applicable fill percentage. No code table is reproduced.

EMT Conduit Fill Chart

Maximum conductor count for electrical metallic tubing, computed from published internal diameters and nominal THHN outside diameters.

Quick answer

1/2 inch EMT holds 9 12 AWG THHN conductors and 3/4 inch EMT holds 16; for 10 AWG the same sizes hold 5 and 10. Fill limits are 40% of internal area for three or more conductors, 31% for two and 53% for one. Grounds and neutrals count.

EMT worked examples

1/2 in EMT conduit fill is 9 12 AWG THHN or 5 10 AWG. In 3/4 in EMT you can install 16 12 AWG conductors, though ampacity adjustment for that many current-carrying conductors normally makes a smaller count the practical limit.

For larger wire, 6 #6 THHN conductors fit in 1 in EMT, and 26 in 2 in EMT. EMT has the thinnest wall of the metal raceways, so at any given trade size it carries the highest count — swapping the same run to IMC or RMC reduces it.

EMT (electrical metallic tubing) — maximum THHN/THWN-2 conductors

Same-size conductors only. Mixed sizes need the conduit fill calculator.

Wire size	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	2-1/2"	3"	3-1/2"	4"
14 AWG	12	22	35	61	84	138	200	200	200	200
12 AWG	9	16	26	45	61	101	176	200	200	200
10 AWG	5	10	16	28	38	63	110	167	200	200
8 AWG	3	5	9	16	22	36	63	96	126	161
6 AWG	1	4	6	11	16	26	46	69	91	116
4 AWG	1	2	4	7	9	16	28	42	56	71
3 AWG	1	1	3	6	8	13	24	36	47	60
2 AWG	1	1	2	5	7	11	20	30	39	50
1 AWG	1	1	1	3	5	8	14	22	29	37
1/0 AWG	—	1	1	3	4	7	12	19	24	31
2/0 AWG	—	1	1	2	3	6	10	15	20	26
3/0 AWG	—	1	1	1	3	5	8	13	17	22
4/0 AWG	—	—	1	1	1	4	7	10	14	18

Counts computed at 53% for one conductor, 31% for two and 40% for three or more.

Published standard

EMT internal area by trade size

Trade size	EMT area
1/2"	0.304 (0.122)
3/4"	0.533 (0.213)
1"	0.864 (0.346)
1-1/4"	1.496 (0.598)
1-1/2"	2.036 (0.814)
2"	3.356 (1.342)
2-1/2"	5.858 (2.343)
3"	8.846 (3.538)
3-1/2"	11.545 (4.618)
4"	14.753 (5.901)

Total internal cross-sectional area in square inches, with the 40% usable figure in brackets.

Source & method: Area is A = π × (id / 2)². Internal diameters are nominal published product dimensions; see the methodology page.

Conductor outside diameters used

Size	Insulated OD (in)	Area (sq in)
18 AWG	0.084	0.0055
16 AWG	0.096	0.0072
14 AWG	0.111	0.0097
12 AWG	0.130	0.0133
10 AWG	0.164	0.0211
8 AWG	0.216	0.0366
6 AWG	0.254	0.0507
4 AWG	0.324	0.0824
3 AWG	0.352	0.0973
2 AWG	0.384	0.1158
1 AWG	0.446	0.1562
1/0 AWG	0.486	0.1855
2/0 AWG	0.532	0.2223
3/0 AWG	0.581	0.2651
4/0 AWG	0.642	0.3237
250 kcmil	0.711	0.3970
300 kcmil	0.766	0.4608
350 kcmil	0.817	0.5242
400 kcmil	0.864	0.5863
500 kcmil	0.949	0.7073
600 kcmil	1.051	0.8676
750 kcmil	1.158	1.0532

Nominal THHN/THWN-2 insulated outside diameter and the area each conductor consumes.

Frequently asked

How many 12 AWG wires fit in 1/2 inch EMT?: Using nominal THHN outside diameters and the 40% fill rule, 9 12 AWG conductors fit in 1/2 inch EMT. Every conductor counts, including the neutral and the equipment grounding conductor.
What is the maximum fill percentage for EMT?: 40% of the internal cross-sectional area for three or more conductors, 31% for exactly two and 53% for a single conductor. Nipples 24 inches or shorter are permitted at 60%.
What size EMT do I need for three 10 AWG conductors?: Three 10 AWG THHN conductors need at least 1/2 inch EMT at 40% fill. Add a fourth conductor and re-check, because the count changes the usable area.
Does the ground wire count toward conduit fill?: Yes. Fill counts every conductor in the raceway. Grounds are excluded only from the ampacity adjustment count for current-carrying conductors, never from fill.
Where do these EMT numbers come from?: Internal diameters are published product dimensions from the relevant ANSI/UL/ASTM product standards. Area is computed as pi times radius squared, and the conductor count is the largest whole number that fits inside the applicable fill percentage. No code table is reproduced.

Mixed conductor sizes

These tables cover one conductor size at a time. Use the conduit fill calculator for mixed sizes, or see the full conduit fill chart for every raceway type side by side.