Beams, channels & columns · Size & tolerance table

American standard C channels (ASTM A6)

Standard: ASTM A6/A6M

C shapes are the American standard channels, with sloped inner flange faces, designated by depth in inches and weight in lb/ft (C10x20) or in metric by depth in mm and mass in kg/m (C250x30). The heavier MC (miscellaneous channel) series is listed separately in ASTM A6 and is not shown here.

xb is the distance from the back of the web to the centroid, needed to work out the eccentricity of a load on a channel.

C channel cross-section with depth d, flange width bf, web thickness tw, flange thickness tf and centroid distance xb

C3 to C15 — inch units

Designation	Weight lb/ft	A in²	d in	bf in	tw in	tf in	Ix in⁴	Iy in⁴	xb in
C15x50	50	14.7	15	3.716	0.716	0.65	404	11	0.798
C15x40	40	11.8	15	3.52	0.52	0.65	349	9.23	0.777
C15x33.9	33.9	9.96	15	3.4	0.4	0.65	315	8.13	0.787
C12x30	30	8.82	12	3.17	0.51	0.501	162	5.14	0.674
C12x25	25	7.35	12	3.047	0.387	0.501	144	4.47	0.674
C12x20.7	20.7	6.09	12	2.942	0.282	0.501	129	3.88	0.698
C10x30	30	8.82	10	3.033	0.673	0.436	103	3.94	0.649
C10x25	25	7.35	10	2.886	0.526	0.436	91.2	3.36	0.617
C10x20	20	5.88	10	2.739	0.379	0.436	78.9	2.81	0.606
C10x15.3	15.3	4.49	10	2.6	0.24	0.436	67.4	2.28	0.634
C9x20	20	5.88	9	2.648	0.448	0.413	60.9	2.42	0.583
C9x15	15	4.41	9	2.485	0.285	0.413	51	1.93	0.586
C9x13.4	13.4	3.94	9	2.433	0.233	0.413	47.9	1.76	0.601
C8x13.75	13.75	4.04	8	2.343	0.303	0.39	36.1	1.53	0.553
C8x11.5	11.5	3.38	8	2.26	0.22	0.39	32.6	1.32	0.571
C7x14.75	14.75	4.33	7	2.299	0.419	0.366	27.2	1.38	0.532
C7x12.25	12.25	3.6	7	2.194	0.314	0.366	24.2	1.17	0.525
C7x9.8	9.8	2.87	7	2.09	0.21	0.366	21.3	0.968	0.54
C6x13	13	3.83	6	2.157	0.437	0.343	17.4	1.05	0.514
C6x10.5	10.5	3.09	6	2.034	0.314	0.343	15.2	0.866	0.499
C6x8.2	8.2	2.4	6	1.92	0.2	0.343	13.1	0.693	0.511
C5x9	9	2.64	5	1.885	0.325	0.32	8.9	0.632	0.478
C5x6.7	6.7	1.97	5	1.75	0.19	0.32	7.49	0.479	0.484
C4x7.25	7.25	2.13	4	1.721	0.321	0.296	4.59	0.433	0.459
C4x5.4	5.4	1.59	4	1.584	0.184	0.296	3.85	0.319	0.457
C3x6	6	1.76	3	1.596	0.356	0.273	2.07	0.305	0.455
C3x5	5	1.47	3	1.498	0.258	0.273	1.85	0.247	0.438
C3x4.1	4.1	1.21	3	1.41	0.17	0.273	1.66	0.197	0.436

C200 to C380 — metric units

Designation	Inch designation	G kg/m	d mm	bf mm	tw mm	tf mm	Ix ×10⁶ mm⁴	Sx cm³	Zx cm³	rx mm	Iy ×10⁶ mm⁴	Sy cm³	Zy cm³	ry mm
C 200x17	C 8x11.5	17	203.0	57.40	5.59	9.90	13.6	134	156	79.0	0.549	12.8	25.9	15.9
C 200x20	C 8x13.75	20	203.0	59.50	7.70	9.90	15.0	148	179	75.8	0.637	14.0	28.3	15.6
C 200x28	C 8x18.75	28	203.0	64.20	12.40	9.90	18.3	180	226	71.8	0.824	16.5	35.6	15.2
C 250x23	C 10x15.3	23	254.0	66.00	6.10	11.10	28.1	221	259	98.4	0.949	19.0	38.5	18.1
C 250x30	C 10x20	30	254.0	69.60	9.63	11.10	32.8	258	316	93.0	1.17	21.6	44.4	17.6
C 250x37	C 10x25	37	254.0	73.30	13.40	11.10	38.0	299	377	89.5	1.40	24.3	52.3	17.2
C 250x45	C 10x30	45	254.0	77.00	17.10	11.10	42.9	338	436	86.8	1.64	27.1	61.9	17.0
C 310x31	C 12x20.7	31	305.0	74.70	7.16	12.70	53.7	352	416	117	1.61	28.3	57.2	20.2
C 310x37	C 12x25	37	305.0	77.40	9.83	12.70	59.9	393	479	112	1.86	30.9	62.9	19.8
C 310x45	C 12x30	45	305.0	80.50	13.00	12.70	67.4	442	551	109	2.14	33.8	71.0	19.4
C 380x50	C 15x33.9	50	381.0	86.40	10.20	16.50	131	688	826	143	3.38	50.9	102	22.9
C 380x60	C 15x40	60	381.0	89.40	13.20	16.50	145	761	937	138	3.84	55.1	113	22.5
C 380x74	C 15x50	74	381.0	94.40	18.20	16.50	168	882	1120	133	4.58	61.8	134	22.0

Notes

Weight in lb/ft is close to 3.4 × the area in in². In the metric table the section moduli (10³ mm³) are given as the equal value in cm³.