American Standard B36.10 Pipe Sizes & Schedules

Quick Reference

American Standard B36.10: pipe sizes for carbon/alloy steel (A53, A106, A333, A335). American Standard B36.19: pipe sizes for stainless/nickel alloy (A312, A790, B161). Schedules: 5, 10, 20, 30, 40 (STD), 60, 80 (XS), 100-160, XXS. Tolerances: OD ±1/64” (≤NPS 10), ±1% (>NPS 12); WT ±12.5%.

Official Dimensions

The values on this page are for general reference only. The official and complete dimensions are published in the standards themselves: see the official pages of B36.10M (welded and seamless wrought steel pipe) and B36.19M (stainless steel pipe) on the publisher’s website.

American Standard B36.10 Pipe Size Chart (Carbon & Alloy Steel Pipe Sizes)

The American Standard B36.10 pipe size chart (also known as the steel pipe dimensions chart) is a standardized reference that defines the dimensions and physical properties of welded and seamless wrought steel pipes for high and low temperatures and pressures (carbon and alloy steel only).

The chart lists the pipe’s outside diameter (OD), wall thickness (expressed as schedule numbers or, for very thick-walled pipes, in inches or millimeters), weight per unit length, and inside diameter (ID) for each nominal pipe size (NPS).

The American Standard B36.10 chart applies to carbon steel pipes and alloy steel pipes. For stainless steel, duplex, super duplex, and nickel alloy pipes (as well as other non-ferrous pipes), the American Standard B36.19 pipe size chart must be applied.

American Standard B36.10 Wall Thickness (mm)

NPS	OD (mm)	Sch 5	Sch 10	Sch 20	Sch 30	Sch 40	Sch STD	Sch 60	Sch 80	Sch XS	Sch 100	Sch 120	Sch 140	Sch 160	Sch XXS
1/8	10.3	-	1.24	-	-	1.73	1.73	-	2.41	2.41	-	-	-	-	-
1/4	13.7	-	1.65	-	-	2.24	2.24	-	3.02	3.02	-	-	-	-	-
3/8	17.1	-	1.65	-	-	2.31	2.31	-	3.20	3.20	-	-	-	-	-
1/2	21.3	1.65	2.11	-	-	2.77	2.77	-	3.73	3.73	-	-	-	4.78	7.47
3/4	26.7	1.65	2.11	-	-	2.87	2.87	-	3.91	3.91	-	-	-	5.56	7.82
1	33.4	1.65	2.77	-	-	3.38	3.38	-	4.55	4.55	-	-	-	6.35	9.09
1 1/4	42.2	1.65	2.77	-	-	3.56	3.56	-	4.85	4.85	-	-	-	6.35	9.70
1 1/2	48.3	1.65	2.77	-	-	3.68	3.68	-	5.08	5.08	-	-	-	7.14	10.15
2	60.3	1.65	2.77	-	-	3.91	3.91	-	5.54	5.54	-	-	-	8.74	11.07
2 1/2	73.0	2.11	3.05	-	-	5.16	5.16	-	7.01	7.01	-	-	-	9.53	14.02
3	88.9	2.11	3.05	-	-	5.49	5.49	-	7.62	7.62	-	-	-	11.13	15.24
3 1/2	101.6	2.11	3.05	-	-	5.74	5.74	-	8.08	8.08	-	-	-	-	16.15
4	114.3	2.11	3.05	-	-	6.02	6.02	-	8.56	8.56	-	11.13	13.49	17.12	17.12
5	141.3	2.77	3.40	-	-	6.55	6.55	-	9.53	9.53	-	12.70	15.88	19.05	19.05
6	168.3	2.77	3.40	-	-	7.11	7.11	-	10.97	10.97	12.70	14.27	-	18.26	21.95
8	219.1	2.77	3.76	6.35	7.04	8.18	8.18	10.31	12.70	12.70	15.09	18.26	20.62	23.01	22.23
10	273.1	3.40	4.19	6.35	7.80	9.27	9.27	12.70	15.09	12.70	18.26	21.44	25.40	28.58	25.40
12	323.9	3.96	4.57	6.35	8.38	10.31	9.53	14.27	17.48	12.70	21.44	25.40	28.58	33.32	25.40
14	355.6	3.96	6.35	7.92	9.53	11.13	9.53	15.09	19.05	12.70	23.83	27.79	31.75	35.71	-
16	406.4	4.19	6.35	7.92	9.53	12.70	9.53	16.66	21.44	12.70	26.19	30.96	36.53	40.49	-
18	457.2	4.19	6.35	7.92	11.13	14.27	9.53	19.05	23.83	12.70	29.36	34.93	39.67	45.24	-
20	508.0	-	6.35	9.53	12.70	15.09	9.53	20.62	26.19	12.70	32.54	38.10	44.45	50.01	-
22	558.8	-	6.35	9.53	12.70	-	9.53	22.23	28.58	12.70	34.93	41.28	47.63	53.98	-
24	609.6	-	6.35	9.53	14.27	17.48	9.53	24.61	30.96	12.70	38.89	46.02	52.37	59.54	-
26	660.4	6.35	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
28	711.2	6.35	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
30	762.0	6.35	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
32	812.8	6.35	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
34	863.6	6.35	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
36	914.4	6.35	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
40	1016.0	-	-	-	-	-	9.53	-	-	12.70	-	-	-	-	-
42	1066.8	-	7.92	-	-	-	9.53	-	-	12.70	-	-	-	-	-
48	1219.2	-	-	-	-	-	9.53	-	-	12.70	-	-	-	-	-

American Standard B36.10 Pipe Weight (kg/m)

NPS	OD (mm)	Sch 5	Sch 10	Sch 20	Sch 30	Sch 40	Sch STD	Sch 60	Sch 80	Sch XS	Sch 100	Sch 120	Sch 140	Sch 160	Sch XXS
1/8	10.3	-	0.28	-	-	0.37	0.37	-	0.47	0.47	-	-	-	-	-
1/4	13.7	-	0.49	-	-	0.63	0.63	-	0.80	0.80	-	-	-	-	-
3/8	17.1	-	0.63	-	-	0.84	0.84	-	1.10	1.10	-	-	-	-	-
1/2	21.3	0.80	1.00	-	-	1.27	1.27	-	1.62	1.62	-	-	-	1.95	2.55
3/4	26.7	1.02	1.28	-	-	1.69	1.69	-	2.20	2.20	-	-	-	2.90	3.64
1	33.4	1.29	2.09	-	-	2.50	2.50	-	3.24	3.24	-	-	-	4.24	5.45
1 1/4	42.2	1.65	2.69	-	-	3.39	3.39	-	4.47	4.47	-	-	-	5.61	7.77
1 1/2	48.3	1.90	3.11	-	-	4.05	4.05	-	5.41	5.41	-	-	-	7.25	9.56
2	60.3	2.39	3.93	-	-	5.44	5.44	-	7.48	7.48	-	-	-	11.11	13.44
2 1/2	73.0	3.69	5.26	-	-	8.63	8.63	-	11.41	11.41	-	-	-	14.92	20.39
3	88.9	4.51	6.45	-	-	11.29	11.29	-	15.27	15.27	-	-	-	21.35	27.68
3 1/2	101.6	5.18	7.40	-	-	13.57	13.57	-	18.63	18.63	-	-	-	-	34.05
4	114.3	5.84	8.36	-	-	16.07	16.07	-	22.32	22.32	-	28.32	33.54	41.03	41.03
5	141.3	9.47	11.57	-	-	21.77	21.77	-	30.97	30.97	-	40.28	49.11	57.43	57.43
6	168.3	11.32	13.84	-	-	28.26	28.26	-	42.56	42.56	48.73	54.20	-	67.56	79.22
8	219.1	14.78	19.96	33.31	36.81	42.55	42.55	53.08	64.64	64.64	75.92	90.44	100.9	111.3	107.9
10	273.1	22.63	27.78	41.77	51.03	60.31	60.31	81.55	96.01	81.55	114.7	133.1	155.1	172.3	155.1
12	323.9	31.25	36.00	49.73	65.20	79.73	73.88	109.0	132.1	97.46	160.0	187.0	208.1	238.8	187.0
14	355.6	34.36	54.69	67.90	81.33	94.55	81.33	126.7	158.1	107.4	195.0	224.7	253.6	281.7	-
16	406.4	41.56	62.64	77.83	93.27	123.3	93.27	160.1	203.5	123.3	245.7	286.6	333.2	365.4	-
18	457.2	46.81	70.57	87.71	122.4	155.8	105.2	205.7	254.6	139.2	309.6	363.6	408.3	459.4	-
20	508.0	-	78.55	117.2	155.1	183.4	117.2	247.8	311.2	155.1	381.5	441.5	508.1	564.8	-
22	558.8	-	86.54	129.1	171.1	-	129.1	294.3	373.8	171.1	451.4	527.0	600.6	672.3	-
24	609.6	-	94.53	141.1	209.6	255.4	141.1	355.3	442.1	187.1	547.7	640.0	720.2	808.2	-
26	660.4	102.4	127.4	-	-	-	152.9	-	-	202.7	-	-	-	-	-
28	711.2	110.3	137.3	-	-	-	164.9	-	-	218.7	-	-	-	-	-
30	762.0	118.3	147.3	-	-	-	176.8	-	-	234.7	-	-	-	-	-
32	812.8	126.3	157.2	-	-	-	188.8	-	-	250.6	-	-	-	-	-
34	863.6	134.3	167.2	-	-	-	200.3	-	-	266.6	-	-	-	-	-
36	914.4	142.1	177.0	-	-	-	212.6	-	-	282.3	-	-	-	-	-
40	1016.0	-	-	-	-	-	236.5	-	-	314.2	-	-	-	-	-
42	1066.8	-	207.9	-	-	-	248.5	-	-	330.2	-	-	-	-	-
48	1219.2	-	-	-	-	-	284.2	-	-	377.8	-	-	-	-	-

American Standard B36.10 Wall Thickness (inches)

NPS	OD (in)	Sch 5	Sch 10	Sch 20	Sch 30	Sch 40	Sch STD	Sch 60	Sch 80	Sch XS	Sch 100	Sch 120	Sch 140	Sch 160	Sch XXS
1/8	0.405	-	0.049	-	-	0.068	0.068	-	0.095	0.095	-	-	-	-	-
1/4	0.540	-	0.065	-	-	0.088	0.088	-	0.119	0.119	-	-	-	-	-
3/8	0.675	-	0.065	-	-	0.091	0.091	-	0.126	0.126	-	-	-	-	-
1/2	0.840	0.065	0.083	-	-	0.109	0.109	-	0.147	0.147	-	-	-	0.188	0.294
3/4	1.050	0.065	0.083	-	-	0.113	0.113	-	0.154	0.154	-	-	-	0.219	0.308
1	1.315	0.065	0.109	-	-	0.133	0.133	-	0.179	0.179	-	-	-	0.250	0.358
1 1/4	1.660	0.065	0.109	-	-	0.140	0.140	-	0.191	0.191	-	-	-	0.250	0.382
1 1/2	1.900	0.065	0.109	-	-	0.145	0.145	-	0.200	0.200	-	-	-	0.281	0.400
2	2.375	0.065	0.109	-	-	0.154	0.154	-	0.218	0.218	-	-	-	0.344	0.436
2 1/2	2.875	0.083	0.120	-	-	0.203	0.203	-	0.276	0.276	-	-	-	0.375	0.552
3	3.500	0.083	0.120	-	-	0.216	0.216	-	0.300	0.300	-	-	-	0.438	0.600
3 1/2	4.000	0.083	0.120	-	-	0.226	0.226	-	0.318	0.318	-	-	-	-	0.636
4	4.500	0.083	0.120	-	-	0.237	0.237	-	0.337	0.337	-	0.438	0.531	0.674	0.674
5	5.563	0.109	0.134	-	-	0.258	0.258	-	0.375	0.375	-	0.500	0.625	0.750	0.750
6	6.625	0.109	0.134	-	-	0.280	0.280	-	0.432	0.432	0.500	0.562	-	0.719	0.864
8	8.625	0.109	0.148	0.250	0.277	0.322	0.322	0.406	0.500	0.500	0.594	0.719	0.812	0.906	0.875
10	10.750	0.134	0.165	0.250	0.307	0.365	0.365	0.500	0.594	0.500	0.719	0.844	1.000	1.125	1.000
12	12.750	0.156	0.180	0.250	0.330	0.406	0.375	0.562	0.688	0.500	0.844	1.000	1.125	1.312	1.000
14	14.000	0.156	0.250	0.312	0.375	0.438	0.375	0.594	0.750	0.500	0.938	1.094	1.250	1.406	-
16	16.000	0.165	0.250	0.312	0.375	0.500	0.375	0.656	0.844	0.500	1.031	1.219	1.438	1.594	-
18	18.000	0.165	0.250	0.312	0.438	0.562	0.375	0.750	0.938	0.500	1.156	1.375	1.562	1.781	-
20	20.000	-	0.250	0.375	0.500	0.594	0.375	0.812	1.031	0.500	1.281	1.500	1.750	1.969	-
22	22.000	-	0.250	0.375	0.500	-	0.375	0.875	1.125	0.500	1.375	1.625	1.875	2.125	-
24	24.000	-	0.250	0.375	0.562	0.688	0.375	0.969	1.219	0.500	1.531	1.812	2.062	2.344	-
26	26.000	0.250	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
28	28.000	0.250	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
30	30.000	0.250	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
32	32.000	0.250	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
34	34.000	0.250	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
36	36.000	0.250	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
40	40.000	-	-	-	-	-	0.375	-	-	0.500	-	-	-	-	-
42	42.000	-	0.312	-	-	-	0.375	-	-	0.500	-	-	-	-	-
48	48.000	-	-	-	-	-	0.375	-	-	0.500	-	-	-	-	-

American Standard B36.10 Pipe Weight (lbs/ft)

NPS	OD (in)	Sch 5	Sch 10	Sch 20	Sch 30	Sch 40	Sch STD	Sch 60	Sch 80	Sch XS	Sch 100	Sch 120	Sch 140	Sch 160	Sch XXS
1/8	0.405	-	0.19	-	-	0.24	0.24	-	0.31	0.31	-	-	-	-	-
1/4	0.540	-	0.33	-	-	0.42	0.42	-	0.54	0.54	-	-	-	-	-
3/8	0.675	-	0.42	-	-	0.57	0.57	-	0.74	0.74	-	-	-	-	-
1/2	0.840	0.54	0.67	-	-	0.85	0.85	-	1.09	1.09	-	-	-	1.31	1.71
3/4	1.050	0.68	0.86	-	-	1.13	1.13	-	1.47	1.47	-	-	-	1.94	2.44
1	1.315	0.87	1.40	-	-	1.68	1.68	-	2.17	2.17	-	-	-	2.84	3.66
1 1/4	1.660	1.11	1.81	-	-	2.27	2.27	-	3.00	3.00	-	-	-	3.77	5.21
1 1/2	1.900	1.28	2.09	-	-	2.72	2.72	-	3.63	3.63	-	-	-	4.86	6.41
2	2.375	1.60	2.64	-	-	3.65	3.65	-	5.02	5.02	-	-	-	7.46	9.03
2 1/2	2.875	2.48	3.53	-	-	5.79	5.79	-	7.66	7.66	-	-	-	10.01	13.70
3	3.500	3.03	4.33	-	-	7.58	7.58	-	10.25	10.25	-	-	-	14.32	18.58
3 1/2	4.000	3.47	4.97	-	-	9.11	9.11	-	12.51	12.51	-	-	-	-	22.85
4	4.500	3.92	5.61	-	-	10.79	10.79	-	14.98	14.98	-	19.01	22.51	27.54	27.54
5	5.563	6.36	7.77	-	-	14.62	14.62	-	20.78	20.78	-	27.04	32.96	38.55	38.55
6	6.625	7.59	9.29	-	-	18.97	18.97	-	28.57	28.57	32.71	36.39	-	45.35	53.16
8	8.625	9.93	13.40	22.36	24.70	28.55	28.55	35.64	43.39	43.39	50.95	60.71	67.76	74.69	72.42
10	10.750	15.19	18.65	28.04	34.24	40.48	40.48	54.74	64.43	54.74	77.03	89.29	104.1	115.7	104.1
12	12.750	21.07	24.17	33.38	43.77	53.52	49.56	73.15	88.63	65.42	107.5	125.5	139.7	160.3	125.5
14	14.000	23.07	36.71	45.68	54.57	63.44	54.57	85.05	106.1	72.09	130.9	150.9	170.2	189.1	-
16	16.000	27.90	42.05	52.36	62.58	82.77	62.58	107.5	136.6	82.77	164.8	192.4	223.6	245.3	-
18	18.000	31.43	47.39	59.03	82.15	104.8	70.59	138.2	170.9	93.45	208.0	244.1	274.2	308.5	-
20	20.000	-	52.73	78.60	104.1	122.9	78.60	166.4	208.9	104.1	256.1	296.4	341.1	379.0	-
22	22.000	-	58.07	86.61	114.8	-	86.61	197.4	250.8	114.8	302.9	353.6	403.0	451.1	-
24	24.000	-	63.41	94.62	140.8	171.3	94.62	238.4	296.6	125.5	367.4	429.4	483.1	542.1	-
26	26.000	68.75	85.60	-	-	-	102.6	-	-	136.2	-	-	-	-	-
28	28.000	74.09	92.26	-	-	-	110.6	-	-	146.8	-	-	-	-	-
30	30.000	79.43	98.93	-	-	-	118.7	-	-	157.5	-	-	-	-	-
32	32.000	84.77	105.6	-	-	-	126.7	-	-	168.2	-	-	-	-	-
34	34.000	90.11	112.3	-	-	-	134.7	-	-	178.9	-	-	-	-	-
36	36.000	95.45	118.9	-	-	-	142.7	-	-	189.6	-	-	-	-	-
40	40.000	-	-	-	-	-	158.7	-	-	210.9	-	-	-	-	-
42	42.000	-	139.6	-	-	-	166.7	-	-	221.6	-	-	-	-	-
48	48.000	-	-	-	-	-	190.7	-	-	253.6	-	-	-	-	-

⚠️ If you are interested in charts showing only the wall thickness of carbon & alloy steel pipes in inches or in mm by NPS or DN, consult this article.

Common Mistake

Confusing “Sch 40” with “Sch 40S” for stainless steel pipes above NPS 10. Below NPS 10, they’re identical. At NPS 12, Sch 40 is 10.31mm wall per B36.10, but Sch 40S is only 9.53mm per B36.19. Specifying the wrong standard can mean receiving pipe that’s thinner than your design requires.

American Standard B36.19 Pipe Size Chart (for Stainless/nickel Alloy Pipes)

The American Standard B36.19 pipe size chart is a standardized chart that specifies the dimensions and physical properties of stainless steel pipes (and higher alloyed grades) intended for high-temperature, high-pressure applications, as well as for corrosive or high-purity applications. Similar to the American Standard B36.10 chart for carbon and alloy steel pipes, the B36.19 chart focuses specifically on stainless steel pipes, including seamless and welded types.

American Standard B36.19 Wall Thickness (mm) - Stainless Steel Pipes

NPS	OD (mm)	OD (in)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	10.3	0.405	-	1.24	1.73	2.41
1/4	13.7	0.540	-	1.65	2.24	3.02
3/8	17.1	0.675	-	1.65	2.31	3.20
1/2	21.3	0.840	1.65	2.11	2.77	3.73
3/4	26.7	1.050	1.65	2.11	2.87	3.91
1	33.4	1.315	1.65	2.77	3.38	4.55
1 1/4	42.2	1.660	1.65	2.77	3.56	4.85
1 1/2	48.3	1.900	1.65	2.77	3.68	5.08
2	60.3	2.375	1.65	2.77	3.91	5.54
2 1/2	73.0	2.875	2.11	3.05	5.16	7.01
3	88.9	3.500	2.11	3.05	5.49	7.62
3 1/2	101.6	4.000	2.11	3.05	5.74	8.08
4	114.3	4.500	2.11	3.05	6.02	8.56
5	141.3	5.563	2.77	3.40	6.55	9.53
6	168.3	6.625	2.77	3.40	7.11	10.97
8	219.1	8.625	2.77	3.76	8.18	12.70
10	273.1	10.750	3.40	4.19	9.27	12.70
12	323.9	12.750	3.96	4.57	9.53	12.70

American Standard B36.19 Pipe Weight (kg/m) - Stainless Steel Pipes

NPS	OD (mm)	OD (in)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	10.3	0.405	-	0.28	0.37	0.47
1/4	13.7	0.540	-	0.49	0.63	0.80
3/8	17.1	0.675	-	0.63	0.85	1.10
1/2	21.3	0.840	0.80	1.00	1.27	1.62
3/4	26.7	1.050	1.02	1.28	1.68	2.20
1	33.4	1.315	1.29	2.09	2.50	3.24
1 1/4	42.2	1.660	1.65	2.69	3.39	4.47
1 1/2	48.3	1.900	1.90	3.11	4.05	5.41
2	60.3	2.375	2.39	3.93	5.44	7.48
2 1/2	73.0	2.875	3.69	5.26	8.63	11.41
3	88.9	3.500	4.51	6.45	11.29	15.27
3 1/2	101.6	4.000	5.18	7.40	13.57	18.63
4	114.3	4.500	5.84	8.36	16.07	22.32
5	141.3	5.563	9.46	11.57	21.77	30.97
6	168.3	6.625	11.32	13.84	28.26	42.56
8	219.1	8.625	14.78	19.96	42.55	64.64
10	273.1	10.750	22.63	27.78	60.31	81.55
12	323.9	12.750	31.25	36.00	73.88	97.46

American Standard B36.19 Wall Thickness (inches) - Stainless Steel Pipes

NPS	OD (in)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	0.405	-	0.049	0.068	0.095
1/4	0.540	-	0.065	0.088	0.119
3/8	0.675	-	0.065	0.091	0.126
1/2	0.840	0.065	0.083	0.109	0.147
3/4	1.050	0.065	0.083	0.113	0.154
1	1.315	0.065	0.109	0.133	0.179
1 1/4	1.660	0.065	0.109	0.140	0.191
1 1/2	1.900	0.065	0.109	0.145	0.200
2	2.375	0.065	0.109	0.154	0.218
2 1/2	2.875	0.083	0.120	0.203	0.276
3	3.500	0.083	0.120	0.216	0.300
3 1/2	4.000	0.083	0.120	0.226	0.318
4	4.500	0.083	0.120	0.237	0.337
5	5.563	0.109	0.134	0.258	0.375
6	6.625	0.109	0.134	0.280	0.432
8	8.625	0.109	0.148	0.322	0.500
10	10.750	0.134	0.165	0.365	0.500
12	12.750	0.156	0.180	0.375	0.500

American Standard B36.19 Pipe Weight (lbs/ft) - Stainless Steel Pipes

NPS	OD (in)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	0.405	-	0.19	0.25	0.31
1/4	0.540	-	0.33	0.42	0.54
3/8	0.675	-	0.42	0.57	0.74
1/2	0.840	0.54	0.67	0.85	1.09
3/4	1.050	0.69	0.86	1.13	1.48
1	1.315	0.87	1.40	1.68	2.18
1 1/4	1.660	1.11	1.81	2.27	3.00
1 1/2	1.900	1.28	2.09	2.72	3.63
2	2.375	1.60	2.64	3.65	5.02
2 1/2	2.875	2.48	3.53	5.79	7.66
3	3.500	3.03	4.33	7.58	10.25
3 1/2	4.000	3.47	4.97	9.11	12.51
4	4.500	3.92	5.61	10.79	14.98
5	5.563	6.36	7.77	14.62	20.78
6	6.625	7.59	9.29	18.97	28.57
8	8.625	9.93	13.40	28.55	43.39
10	10.750	15.19	18.65	40.48	54.74
12	12.750	21.07	24.17	49.56	65.42

⚠️ If you are interested in charts showing only the wall thickness of stainless steel, duplex, and super duplex steel, nickel alloy pipes in inches or in mm by NPS or DN, consult this article.

Steel Pipes Tolerances (American Standards B36.10 & B36.19)

Diameter Tolerance

American Standards B36.10M (carbon and alloy steel) and B36.19M (stainless steel) specify pipe diameter tolerances to ensure pipes meet the required dimensions for proper fit and function in piping systems.

Tolerance levels vary by manufacturing process (seamless or welded), pipe size, and schedule (wall thickness).

American Standards B36.10M & B36.19M Diameter Tolerances

#	Tolerance Type	Details
1	OD Tolerance for Seamless Pipes	NPS 1/8 to NPS 10: ±1/64 inch (±0.4 mm). NPS 12 and above: ±1% of the nominal diameter.
2	OD Tolerance for Welded Pipes	NPS 1/8 to NPS 10: ±1/64 inch (±0.4 mm). NPS 12 and above: typically ±1% of nominal diameter, but may vary based on welding method and pipe manufacturing process. Refer to specific standards or manufacturer specifications for precise values.
3	Inside Diameter (ID) Tolerance	Not typically specified; inferred from the OD and wall thickness tolerances. For a specific ID tolerance, control the OD and wall thickness within the prescribed tolerances.
4	Wall Thickness Tolerance	Generally ±12.5% of the nominal wall thickness for most pipe sizes and schedules as per American Standards B36.10M and B36.19M.

Pro Tip

The -12.5% wall thickness tolerance is critical for pressure calculations. When sizing pipe for high-pressure service, design using 87.5% of the nominal wall thickness (the minimum guaranteed) rather than the nominal value. I’ve seen engineers specify Sch 40 expecting 6.02mm wall, but receive compliant pipe at 5.27mm that doesn’t meet their pressure requirements.

These tolerances are general guidelines. Specific applications may require tighter tolerances, and some manufacturers offer pipes with tolerances stricter than those in the American Standards. Always refer to the latest edition of the relevant American Standard or consult the pipe manufacturer for the applicable tolerances for your project.

Weight Tolerance

American Standards B36.10 and B36.19 do not explicitly define weight tolerances for pipes. Pipe weight is derived from outside diameter, wall thickness, and material density, so weight per unit length can be calculated from these parameters.

However, actual weight varies due to manufacturing tolerances on wall thickness and diameter. For project-specific weight tolerances, refer to the manufacturer’s standards or the material grade specification.

For applications where weight precision matters (load-bearing structures, transport weight limits), consult the pipe manufacturer for the expected weight range.

Generally accepted weight tolerances for pipes are:

Pipe Size	Weighing Method	Tolerance
NPS 4 (DN100, 114.3mm) and smaller	Weighed in convenient lots	-
NPS 12 (DN300, 323.8mm) and under	Weighed individually	-3.5% / +10%
Over NPS 12 (DN300, 323.8mm)	Weighed individually	-5% / +10%

Field Note

Weight tolerance matters for material verification. If you’re checking delivered pipe against the MTC, calculate expected weight per meter from the dimensions, then apply the -5%/+10% tolerance. Pipe significantly outside this range (especially lighter) suggests possible wall thickness issues - request UT verification before installation.

Quantity Tolerance

American Standards B36.10M and B36.19M do not specify “quantity tolerances” (the acceptable variation in the number of pipes delivered versus ordered). Quantity tolerance falls under procurement contracts, project specifications, or supplier agreements.

Quantity tolerance terms are negotiated between buyer and supplier and should be clearly stated in the purchase order or contract. Common terms include:

Term	Description
Overage or Shortage Allowance	An agreed percentage of the total order quantity that the supplier is permitted to deliver over or under the specified quantity.
Exact Quantity Requirement	Some contracts may require the delivery of the exact quantity specified, with no allowance for overage or underage.
Penalties for Non-compliance	Contracts may specify penalties or remedial actions if the delivered quantity does not comply with the agreed terms.

For large projects, a certain percentage of overage is commonly allowed to account for installation issues, damage, or miscalculations.

Purchasing documents should clearly define how quantity tolerances are handled, including any specific requirements or exceptions.

Length Tolerance

American Standards B36.10M and B36.19M do not provide explicit tolerances for pipe lengths. However, standard industry practices address pipe length tolerances as follows.

Standard Pipe Lengths and Tolerances

Length Type	Tolerance / Range
Fixed Lengths	Defined in the purchase order. Common practice: +0 to +1/4” to +1/2” (+6 mm to +12 mm) per length, depending on total pipe length.
Random Lengths	Single random: 16 to 22 ft (4.9 to 6.7 m). Double random: 35 to 45 ft (10.7 to 13.7 m). Exact tolerance should be specified by the manufacturer or agreed in contract.
Cut Lengths	Tolerances similar to fixed lengths; exact values specified in the contract or project documentation standards.

Project-Specific Requirements

Engineering specifications may define length tolerances more strictly than standard practice. These project-specific requirements take precedence and are negotiated as part of the contract or purchase agreement.

Reference to Standards

Always reference the latest version of the relevant American Standards or applicable project specifications. Where these standards do not define length tolerances, manufacturer standards, purchase agreements, and project specifications govern.

Nominal Pipe Size (NPS) to DN Conversion Chart

The table below converts NPS (Nominal Pipe Size) to the pipe outside diameter in inches, mm, and DN (Nominal Diameter).

PIPE NPS	Pipe outside diameterin inches	Pipe outside diameterin mm	NPS to DNconversion
1/8	0.404	10.26	6
1/4	0.54	13.72	8
3/8	0.675	17.15	10
1/2	0.84	21.34	15
¾	1.05	26.67	20
1	1.315	33.40	25
1 ¼	1.66	42.16	32
1 ½	1.9	48.26	40
2	2.375	60.33	50
2 ½	2.875	73.03	65
3	3.5	88.90	80
3 ½	4	101.60	90
4	4.5	114.30	100
4 ½	5	127.00	115
5	5.563	141.30	125
6	6.625	168.28	150
7	7.625	193.68	-
8	8.625	219.08	200
10	10.75	273.05	250
12	12.75	323.85	300
14	14	355.60	350
16	16	406.40	400
18	18	457.20	450
20	20	508.00	500
22	22	558.80	550
24	24	609.60	600
26	26	660.40	650
28	28	711.20	700
30	30	762.00	750
32	32	812.80	800
34	34	863.60	850
36	36	914.40	900
38	38	965.20	950
40	40	1016.00	1000
42	42	1066.80	1050
44	44	1117.60	1100
46	46	1168.40	1150
48	48	1219.20	120

Sources:

• Wikipedia
• TPMC Steel

For the official and complete dimensions, we recommend purchasing the standards from the publisher’s official pages: B36.10M and B36.19M.

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Frequently Asked Questions

What is the actual outside diameter of a 2-inch pipe?

The actual OD of a NPS 2 (2-inch nominal) pipe is 2.375 inches (60.3 mm) ; not 2.000 inches. For sizes NPS 1/8 through NPS 12, the nominal pipe size does NOT equal the actual outside diameter. Starting from NPS 14 and above, the NPS number matches the actual OD in inches. This is because NPS originally referred to the approximate inside diameter; as wall thicknesses changed, the OD was standardized and the NPS name stayed.

What is the difference between American Standards B36.10 and B36.19?

American Standard B36.10M defines dimensions (OD, wall thickness, weight) for carbon steel and alloy steel welded and seamless pipes. American Standard B36.19M defines dimensions for stainless steel pipes. The key difference: B36.19 uses the "S" suffix for schedules (5S, 10S, 40S, 80S) and some stainless schedules have different wall thicknesses than their B36.10 equivalents ; particularly in smaller sizes. Always verify which standard applies for your material.

How do I calculate pipe weight per meter or per foot?

Pipe weight per unit length = (OD - WT) × WT × C, where OD is outside diameter, WT is wall thickness, and C is a constant: 0.02466 kg/mm²/m for metric or 10.69 lb/in²/ft for imperial (for carbon steel, density 7.85 g/cm³). For stainless steel (density 8.0 g/cm³), multiply by 1.02. For aluminum, multiply by 0.35. Always use the nominal wall thickness ; actual weight may vary by ±10% due to manufacturing tolerances.

What is the thickest available pipe schedule?

The thickest standard schedule is XXS (Double Extra Strong), sometimes written as XXH. For example, NPS 2 XXS has a wall thickness of 0.436 inches (11.07 mm) vs. 0.154 inches for SCH 40. However, for some pipe sizes, SCH 160 can be thicker than XXS ; always check the dimensional tables for the specific NPS. For wall thicknesses beyond XXS, custom-manufactured heavy-wall pipe must be specified.