Pipe Schedule Chart

Outside diameter, wall thickness and inside diameter for steel pipe from NPS 1/8 to NPS 24, per ASME B36.10M (carbon and alloy steel) and ASME B36.19M (stainless). Each cell shows the wall with the resulting ID beneath it.

Carbon and alloy steel pipe (B36.10M), inches

ASME B36.10M pipe dimensions in inches: outside diameter, wall thickness and computed inside diameter by schedule
NPS	DN	OD (in)	Sch 10	Sch 40	STD	Sch 80	XS	Sch 160	XXS
1/8	6	0.405	Not listed	0.068ID 0.269	0.068ID 0.269	0.095ID 0.215	0.095ID 0.215	Not listed	Not listed
1/4	8	0.540	Not listed	0.088ID 0.364	0.088ID 0.364	0.119ID 0.302	0.119ID 0.302	Not listed	Not listed
3/8	10	0.675	Not listed	0.091ID 0.493	0.091ID 0.493	0.126ID 0.423	0.126ID 0.423	Not listed	Not listed
1/2	15	0.840	Not listed	0.109ID 0.622	0.109ID 0.622	0.147ID 0.546	0.147ID 0.546	0.188ID 0.464	0.294ID 0.252
3/4	20	1.050	Not listed	0.113ID 0.824	0.113ID 0.824	0.154ID 0.742	0.154ID 0.742	0.219ID 0.612	0.308ID 0.434
1	25	1.315	Not listed	0.133ID 1.049	0.133ID 1.049	0.179ID 0.957	0.179ID 0.957	0.250ID 0.815	0.358ID 0.599
1-1/4	32	1.660	Not listed	0.140ID 1.380	0.140ID 1.380	0.191ID 1.278	0.191ID 1.278	0.250ID 1.160	0.382ID 0.896
1-1/2	40	1.900	Not listed	0.145ID 1.610	0.145ID 1.610	0.200ID 1.500	0.200ID 1.500	0.281ID 1.338	0.400ID 1.100
2	50	2.375	Not listed	0.154ID 2.067	0.154ID 2.067	0.218ID 1.939	0.218ID 1.939	0.344ID 1.687	0.436ID 1.503
2-1/2	65	2.875	Not listed	0.203ID 2.469	0.203ID 2.469	0.276ID 2.323	0.276ID 2.323	0.375ID 2.125	0.552ID 1.771
3	80	3.500	Not listed	0.216ID 3.068	0.216ID 3.068	0.300ID 2.900	0.300ID 2.900	0.438ID 2.624	0.600ID 2.300
3-1/2	90	4.000	Not listed	0.226ID 3.548	0.226ID 3.548	0.318ID 3.364	0.318ID 3.364	Not listed	Not listed
4	100	4.500	Not listed	0.237ID 4.026	0.237ID 4.026	0.337ID 3.826	0.337ID 3.826	0.531ID 3.438	0.674ID 3.152
5	125	5.563	Not listed	0.258ID 5.047	0.258ID 5.047	0.375ID 4.813	0.375ID 4.813	0.625ID 4.313	0.750ID 4.063
6	150	6.625	Not listed	0.280ID 6.065	0.280ID 6.065	0.432ID 5.761	0.432ID 5.761	0.719ID 5.187	0.864ID 4.897
8	200	8.625	Not listed	0.322ID 7.981	0.322ID 7.981	0.500ID 7.625	0.500ID 7.625	0.906ID 6.813	0.875ID 6.875
10	250	10.750	Not listed	0.365ID 10.020	0.365ID 10.020	0.594ID 9.562	0.500ID 9.750	1.125ID 8.500	1.000ID 8.750
12	300	12.750	Not listed	0.406ID 11.938	0.375ID 12.000	0.688ID 11.374	0.500ID 11.750	1.312ID 10.126	1.000ID 10.750
14	350	14.000	0.250ID 13.500	0.438ID 13.124	0.375ID 13.250	0.750ID 12.500	0.500ID 13.000	1.406ID 11.188	Not listed
16	400	16.000	0.250ID 15.500	0.500ID 15.000	0.375ID 15.250	0.844ID 14.312	0.500ID 15.000	1.594ID 12.812	Not listed
18	450	18.000	0.250ID 17.500	0.562ID 16.876	0.375ID 17.250	0.938ID 16.124	0.500ID 17.000	1.781ID 14.438	Not listed
20	500	20.000	0.250ID 19.500	0.594ID 18.812	0.375ID 19.250	1.031ID 17.938	0.500ID 19.000	1.969ID 16.062	Not listed
22	550	22.000	0.250ID 21.500	Not listed	0.375ID 21.250	1.125ID 19.750	0.500ID 21.000	2.125ID 17.750	Not listed
24	600	24.000	0.250ID 23.500	0.688ID 22.624	0.375ID 23.250	1.219ID 21.562	0.500ID 23.000	2.344ID 19.312	Not listed

Show the same table in millimeters

ASME B36.10M pipe dimensions in millimeters: outside diameter, wall thickness and computed inside diameter by schedule
NPS	DN	OD (mm)	Sch 10	Sch 40	STD	Sch 80	XS	Sch 160	XXS
1/8	6	10.3	Not listed	1.73ID 6.8	1.73ID 6.8	2.41ID 5.5	2.41ID 5.5	Not listed	Not listed
1/4	8	13.7	Not listed	2.24ID 9.2	2.24ID 9.2	3.02ID 7.7	3.02ID 7.7	Not listed	Not listed
3/8	10	17.1	Not listed	2.31ID 12.5	2.31ID 12.5	3.20ID 10.7	3.20ID 10.7	Not listed	Not listed
1/2	15	21.3	Not listed	2.77ID 15.8	2.77ID 15.8	3.73ID 13.9	3.73ID 13.9	4.78ID 11.8	7.47ID 6.4
3/4	20	26.7	Not listed	2.87ID 20.9	2.87ID 20.9	3.91ID 18.8	3.91ID 18.8	5.56ID 15.5	7.82ID 11.0
1	25	33.4	Not listed	3.38ID 26.6	3.38ID 26.6	4.55ID 24.3	4.55ID 24.3	6.35ID 20.7	9.09ID 15.2
1-1/4	32	42.2	Not listed	3.56ID 35.1	3.56ID 35.1	4.85ID 32.5	4.85ID 32.5	6.35ID 29.5	9.70ID 22.8
1-1/2	40	48.3	Not listed	3.68ID 40.9	3.68ID 40.9	5.08ID 38.1	5.08ID 38.1	7.14ID 34.0	10.16ID 27.9
2	50	60.3	Not listed	3.91ID 52.5	3.91ID 52.5	5.54ID 49.3	5.54ID 49.3	8.74ID 42.8	11.07ID 38.2
2-1/2	65	73.0	Not listed	5.16ID 62.7	5.16ID 62.7	7.01ID 59.0	7.01ID 59.0	9.52ID 54.0	14.02ID 45.0
3	80	88.9	Not listed	5.49ID 77.9	5.49ID 77.9	7.62ID 73.7	7.62ID 73.7	11.13ID 66.6	15.24ID 58.4
3-1/2	90	101.6	Not listed	5.74ID 90.1	5.74ID 90.1	8.08ID 85.4	8.08ID 85.4	Not listed	Not listed
4	100	114.3	Not listed	6.02ID 102.3	6.02ID 102.3	8.56ID 97.2	8.56ID 97.2	13.49ID 87.3	17.12ID 80.1
5	125	141.3	Not listed	6.55ID 128.2	6.55ID 128.2	9.52ID 122.3	9.52ID 122.3	15.88ID 109.6	19.05ID 103.2
6	150	168.3	Not listed	7.11ID 154.1	7.11ID 154.1	10.97ID 146.3	10.97ID 146.3	18.26ID 131.7	21.95ID 124.4
8	200	219.1	Not listed	8.18ID 202.7	8.18ID 202.7	12.70ID 193.7	12.70ID 193.7	23.01ID 173.1	22.22ID 174.6
10	250	273.1	Not listed	9.27ID 254.5	9.27ID 254.5	15.09ID 242.9	12.70ID 247.6	28.58ID 215.9	25.40ID 222.3
12	300	323.8	Not listed	10.31ID 303.2	9.52ID 304.8	17.48ID 288.9	12.70ID 298.5	33.32ID 257.2	25.40ID 273.1
14	350	355.6	6.35ID 342.9	11.13ID 333.3	9.52ID 336.5	19.05ID 317.5	12.70ID 330.2	35.71ID 284.2	Not listed
16	400	406.4	6.35ID 393.7	12.70ID 381.0	9.52ID 387.3	21.44ID 363.5	12.70ID 381.0	40.49ID 325.4	Not listed
18	450	457.2	6.35ID 444.5	14.27ID 428.7	9.52ID 438.2	23.83ID 409.5	12.70ID 431.8	45.24ID 366.7	Not listed
20	500	508.0	6.35ID 495.3	15.09ID 477.8	9.52ID 489.0	26.19ID 455.6	12.70ID 482.6	50.01ID 408.0	Not listed
22	550	558.8	6.35ID 546.1	Not listed	9.52ID 539.8	28.58ID 501.7	12.70ID 533.4	53.97ID 450.8	Not listed
24	600	609.6	6.35ID 596.9	17.48ID 574.6	9.52ID 590.6	30.96ID 547.7	12.70ID 584.2	59.54ID 490.5	Not listed

ID = OD - 2 x wall, computed here. Millimeters are converted from the inch values (1 in = 25.4 mm); the standard's own metric columns are rounded separately and can differ in the last digit. Sch 10 is shown for NPS 14 and up. Blank cells are sizes the standard does not list for that schedule, plus NPS 3-1/2 XXS, which is left out here. Intermediate schedules (20, 30, 60, 100, 120, 140) are not shown.

Stainless steel pipe (B36.19M), inches

ASME B36.19M stainless pipe walls in inches: Sch 5S, 10S, 40S and 80S with computed inside diameter
NPS	OD (in)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	0.405	Not listed	0.049ID 0.307	0.068ID 0.269	0.095ID 0.215
1/4	0.540	Not listed	0.065ID 0.410	0.088ID 0.364	0.119ID 0.302
3/8	0.675	Not listed	0.065ID 0.545	0.091ID 0.493	0.126ID 0.423
1/2	0.840	0.065ID 0.710	0.083ID 0.674	0.109ID 0.622	0.147ID 0.546
3/4	1.050	0.065ID 0.920	0.083ID 0.884	0.113ID 0.824	0.154ID 0.742
1	1.315	0.065ID 1.185	0.109ID 1.097	0.133ID 1.049	0.179ID 0.957
1-1/4	1.660	0.065ID 1.530	0.109ID 1.442	0.140ID 1.380	0.191ID 1.278
1-1/2	1.900	0.065ID 1.770	0.109ID 1.682	0.145ID 1.610	0.200ID 1.500
2	2.375	0.065ID 2.245	0.109ID 2.157	0.154ID 2.067	0.218ID 1.939
2-1/2	2.875	0.083ID 2.709	0.120ID 2.635	0.203ID 2.469	0.276ID 2.323
3	3.500	0.083ID 3.334	0.120ID 3.260	0.216ID 3.068	0.300ID 2.900
3-1/2	4.000	0.083ID 3.834	0.120ID 3.760	0.226ID 3.548	0.318ID 3.364
4	4.500	0.083ID 4.334	0.120ID 4.260	0.237ID 4.026	0.337ID 3.826
5	5.563	0.109ID 5.345	0.134ID 5.295	0.258ID 5.047	0.375ID 4.813
6	6.625	0.109ID 6.407	0.134ID 6.357	0.280ID 6.065	0.432ID 5.761
8	8.625	0.109ID 8.407	0.148ID 8.329	0.322ID 7.981	0.500ID 7.625
10	10.750	0.134ID 10.482	0.165ID 10.420	0.365ID 10.020	0.500ID 9.750
12	12.750	0.156ID 12.438	0.180ID 12.390	0.375ID 12.000	0.500ID 11.750
14	14.000	0.156ID 13.688	0.188ID 13.624	Not listed	Not listed
16	16.000	0.165ID 15.670	0.188ID 15.624	Not listed	Not listed
18	18.000	0.165ID 17.670	0.188ID 17.624	Not listed	Not listed
20	20.000	0.188ID 19.624	0.218ID 19.564	Not listed	Not listed
22	22.000	0.188ID 21.624	0.218ID 21.564	Not listed	Not listed
24	24.000	0.218ID 23.564	0.250ID 23.500	Not listed	Not listed

Show the same table in millimeters

ASME B36.19M stainless pipe walls in millimeters: Sch 5S, 10S, 40S and 80S with computed inside diameter
NPS	OD (mm)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	10.3	Not listed	1.24ID 7.8	1.73ID 6.8	2.41ID 5.5
1/4	13.7	Not listed	1.65ID 10.4	2.24ID 9.2	3.02ID 7.7
3/8	17.1	Not listed	1.65ID 13.8	2.31ID 12.5	3.20ID 10.7
1/2	21.3	1.65ID 18.0	2.11ID 17.1	2.77ID 15.8	3.73ID 13.9
3/4	26.7	1.65ID 23.4	2.11ID 22.5	2.87ID 20.9	3.91ID 18.8
1	33.4	1.65ID 30.1	2.77ID 27.9	3.38ID 26.6	4.55ID 24.3
1-1/4	42.2	1.65ID 38.9	2.77ID 36.6	3.56ID 35.1	4.85ID 32.5
1-1/2	48.3	1.65ID 45.0	2.77ID 42.7	3.68ID 40.9	5.08ID 38.1
2	60.3	1.65ID 57.0	2.77ID 54.8	3.91ID 52.5	5.54ID 49.3
2-1/2	73.0	2.11ID 68.8	3.05ID 66.9	5.16ID 62.7	7.01ID 59.0
3	88.9	2.11ID 84.7	3.05ID 82.8	5.49ID 77.9	7.62ID 73.7
3-1/2	101.6	2.11ID 97.4	3.05ID 95.5	5.74ID 90.1	8.08ID 85.4
4	114.3	2.11ID 110.1	3.05ID 108.2	6.02ID 102.3	8.56ID 97.2
5	141.3	2.77ID 135.8	3.40ID 134.5	6.55ID 128.2	9.52ID 122.3
6	168.3	2.77ID 162.7	3.40ID 161.5	7.11ID 154.1	10.97ID 146.3
8	219.1	2.77ID 213.5	3.76ID 211.6	8.18ID 202.7	12.70ID 193.7
10	273.1	3.40ID 266.2	4.19ID 264.7	9.27ID 254.5	12.70ID 247.6
12	323.8	3.96ID 315.9	4.57ID 314.7	9.52ID 304.8	12.70ID 298.5
14	355.6	3.96ID 347.7	4.78ID 346.0	Not listed	Not listed
16	406.4	4.19ID 398.0	4.78ID 396.8	Not listed	Not listed
18	457.2	4.19ID 448.8	4.78ID 447.6	Not listed	Not listed
20	508.0	4.78ID 498.4	5.54ID 496.9	Not listed	Not listed
22	558.8	4.78ID 549.2	5.54ID 547.7	Not listed	Not listed
24	609.6	5.54ID 598.5	6.35ID 596.9	Not listed	Not listed

40S equals STD and 80S equals XS through NPS 12, so they match Sch 40 and Sch 80 up to NPS 10 and NPS 8 respectively; 40S and 80S are not shown above NPS 12.

Need pipe spools, weldments or machined fittings? , or read about welding.

Reading the chart

Inside diameter. The OD is fixed for each NPS, so ID = OD - 2 x wall. NPS 2 Sch 40: 2.375 - 2 x 0.154 = 2.067 in.
Weight. Plain-end carbon steel pipe weighs about 10.69 x (OD - wall) x wall lb/ft with dimensions in inches. NPS 2 Sch 40 works out to 3.66 lb/ft. Stainless is about 2 percent heavier. For other shapes use the metal weight calculator.
Pipe vs tube. Pipe is ordered by NPS and schedule; tube by actual OD and wall. A 1 in tube will not fit a 1 in pipe fitting. See tube and pipe sizes.
Tolerance. Pipe specs (ASTM A53, A106, A312) allow the wall to run under nominal (commonly 12.5 percent under for seamless and welded pipe). Pressure calculations use the minimum wall, not the nominal one in this chart.

Related charts, tools and guides

Tube and pipe sizes Standard bar stock sizes Metal weight calculator Welding TIG welding Tube bending 304 stainless 316 stainless

Frequently asked questions

What does pipe schedule mean?: A schedule is a wall-thickness series. For a given NPS the outside diameter is fixed, so a higher schedule means a thicker wall and a smaller bore. The same schedule number is a thicker wall at a larger NPS: Sch 40 is 0.154 in at NPS 2 and 0.280 in at NPS 6.
Is Sch 40 the same as STD?: Through NPS 10, yes. From NPS 12 up, STD (standard weight) stays at 0.375 in while Sch 40 keeps getting thicker, so NPS 12 Sch 40 is 0.406 in but NPS 12 STD is 0.375 in. Likewise XS equals Sch 80 only through NPS 8 and stays at 0.500 in from NPS 10 up.
Why is 1 in pipe 1.315 in OD?: Nominal pipe size is a trade name, not a measurement. The outside diameter of each NPS was fixed long ago so threads and fittings fit every wall, and the name stayed close to the bore of the old standard-weight pipe. From NPS 14 up, the OD does equal the NPS.
What is the difference between Sch 10 and Sch 10S?: The S schedules (5S, 10S, 40S, 80S) come from ASME B36.19M for stainless pipe. B36.10M, the carbon and alloy steel standard, has its own Sch 10, which in the large sizes is heavier than 10S: at NPS 14 it is 0.250 in against 0.188 in for 10S. When a drawing says Sch 10, confirm which wall is meant.
What does DN mean?: Diametre nominal, the metric name for the same pipe. NPS 2 is DN 50, and its OD is still 60.3 mm. Like NPS, DN is a label, not the outside or inside diameter.

Carbon and alloy steel pipe (B36.10M), inches

ASME B36.10M pipe dimensions in inches: outside diameter, wall thickness and computed inside diameter by schedule
NPS	DN	OD (in)	Sch 10	Sch 40	STD	Sch 80	XS	Sch 160	XXS
1/8	6	0.405	Not listed	0.068ID 0.269	0.068ID 0.269	0.095ID 0.215	0.095ID 0.215	Not listed	Not listed
1/4	8	0.540	Not listed	0.088ID 0.364	0.088ID 0.364	0.119ID 0.302	0.119ID 0.302	Not listed	Not listed
3/8	10	0.675	Not listed	0.091ID 0.493	0.091ID 0.493	0.126ID 0.423	0.126ID 0.423	Not listed	Not listed
1/2	15	0.840	Not listed	0.109ID 0.622	0.109ID 0.622	0.147ID 0.546	0.147ID 0.546	0.188ID 0.464	0.294ID 0.252
3/4	20	1.050	Not listed	0.113ID 0.824	0.113ID 0.824	0.154ID 0.742	0.154ID 0.742	0.219ID 0.612	0.308ID 0.434
1	25	1.315	Not listed	0.133ID 1.049	0.133ID 1.049	0.179ID 0.957	0.179ID 0.957	0.250ID 0.815	0.358ID 0.599
1-1/4	32	1.660	Not listed	0.140ID 1.380	0.140ID 1.380	0.191ID 1.278	0.191ID 1.278	0.250ID 1.160	0.382ID 0.896
1-1/2	40	1.900	Not listed	0.145ID 1.610	0.145ID 1.610	0.200ID 1.500	0.200ID 1.500	0.281ID 1.338	0.400ID 1.100
2	50	2.375	Not listed	0.154ID 2.067	0.154ID 2.067	0.218ID 1.939	0.218ID 1.939	0.344ID 1.687	0.436ID 1.503
2-1/2	65	2.875	Not listed	0.203ID 2.469	0.203ID 2.469	0.276ID 2.323	0.276ID 2.323	0.375ID 2.125	0.552ID 1.771
3	80	3.500	Not listed	0.216ID 3.068	0.216ID 3.068	0.300ID 2.900	0.300ID 2.900	0.438ID 2.624	0.600ID 2.300
3-1/2	90	4.000	Not listed	0.226ID 3.548	0.226ID 3.548	0.318ID 3.364	0.318ID 3.364	Not listed	Not listed
4	100	4.500	Not listed	0.237ID 4.026	0.237ID 4.026	0.337ID 3.826	0.337ID 3.826	0.531ID 3.438	0.674ID 3.152
5	125	5.563	Not listed	0.258ID 5.047	0.258ID 5.047	0.375ID 4.813	0.375ID 4.813	0.625ID 4.313	0.750ID 4.063
6	150	6.625	Not listed	0.280ID 6.065	0.280ID 6.065	0.432ID 5.761	0.432ID 5.761	0.719ID 5.187	0.864ID 4.897
8	200	8.625	Not listed	0.322ID 7.981	0.322ID 7.981	0.500ID 7.625	0.500ID 7.625	0.906ID 6.813	0.875ID 6.875
10	250	10.750	Not listed	0.365ID 10.020	0.365ID 10.020	0.594ID 9.562	0.500ID 9.750	1.125ID 8.500	1.000ID 8.750
12	300	12.750	Not listed	0.406ID 11.938	0.375ID 12.000	0.688ID 11.374	0.500ID 11.750	1.312ID 10.126	1.000ID 10.750
14	350	14.000	0.250ID 13.500	0.438ID 13.124	0.375ID 13.250	0.750ID 12.500	0.500ID 13.000	1.406ID 11.188	Not listed
16	400	16.000	0.250ID 15.500	0.500ID 15.000	0.375ID 15.250	0.844ID 14.312	0.500ID 15.000	1.594ID 12.812	Not listed
18	450	18.000	0.250ID 17.500	0.562ID 16.876	0.375ID 17.250	0.938ID 16.124	0.500ID 17.000	1.781ID 14.438	Not listed
20	500	20.000	0.250ID 19.500	0.594ID 18.812	0.375ID 19.250	1.031ID 17.938	0.500ID 19.000	1.969ID 16.062	Not listed
22	550	22.000	0.250ID 21.500	Not listed	0.375ID 21.250	1.125ID 19.750	0.500ID 21.000	2.125ID 17.750	Not listed
24	600	24.000	0.250ID 23.500	0.688ID 22.624	0.375ID 23.250	1.219ID 21.562	0.500ID 23.000	2.344ID 19.312	Not listed

Show the same table in millimeters

ASME B36.10M pipe dimensions in millimeters: outside diameter, wall thickness and computed inside diameter by schedule
NPS	DN	OD (mm)	Sch 10	Sch 40	STD	Sch 80	XS	Sch 160	XXS
1/8	6	10.3	Not listed	1.73ID 6.8	1.73ID 6.8	2.41ID 5.5	2.41ID 5.5	Not listed	Not listed
1/4	8	13.7	Not listed	2.24ID 9.2	2.24ID 9.2	3.02ID 7.7	3.02ID 7.7	Not listed	Not listed
3/8	10	17.1	Not listed	2.31ID 12.5	2.31ID 12.5	3.20ID 10.7	3.20ID 10.7	Not listed	Not listed
1/2	15	21.3	Not listed	2.77ID 15.8	2.77ID 15.8	3.73ID 13.9	3.73ID 13.9	4.78ID 11.8	7.47ID 6.4
3/4	20	26.7	Not listed	2.87ID 20.9	2.87ID 20.9	3.91ID 18.8	3.91ID 18.8	5.56ID 15.5	7.82ID 11.0
1	25	33.4	Not listed	3.38ID 26.6	3.38ID 26.6	4.55ID 24.3	4.55ID 24.3	6.35ID 20.7	9.09ID 15.2
1-1/4	32	42.2	Not listed	3.56ID 35.1	3.56ID 35.1	4.85ID 32.5	4.85ID 32.5	6.35ID 29.5	9.70ID 22.8
1-1/2	40	48.3	Not listed	3.68ID 40.9	3.68ID 40.9	5.08ID 38.1	5.08ID 38.1	7.14ID 34.0	10.16ID 27.9
2	50	60.3	Not listed	3.91ID 52.5	3.91ID 52.5	5.54ID 49.3	5.54ID 49.3	8.74ID 42.8	11.07ID 38.2
2-1/2	65	73.0	Not listed	5.16ID 62.7	5.16ID 62.7	7.01ID 59.0	7.01ID 59.0	9.52ID 54.0	14.02ID 45.0
3	80	88.9	Not listed	5.49ID 77.9	5.49ID 77.9	7.62ID 73.7	7.62ID 73.7	11.13ID 66.6	15.24ID 58.4
3-1/2	90	101.6	Not listed	5.74ID 90.1	5.74ID 90.1	8.08ID 85.4	8.08ID 85.4	Not listed	Not listed
4	100	114.3	Not listed	6.02ID 102.3	6.02ID 102.3	8.56ID 97.2	8.56ID 97.2	13.49ID 87.3	17.12ID 80.1
5	125	141.3	Not listed	6.55ID 128.2	6.55ID 128.2	9.52ID 122.3	9.52ID 122.3	15.88ID 109.6	19.05ID 103.2
6	150	168.3	Not listed	7.11ID 154.1	7.11ID 154.1	10.97ID 146.3	10.97ID 146.3	18.26ID 131.7	21.95ID 124.4
8	200	219.1	Not listed	8.18ID 202.7	8.18ID 202.7	12.70ID 193.7	12.70ID 193.7	23.01ID 173.1	22.22ID 174.6
10	250	273.1	Not listed	9.27ID 254.5	9.27ID 254.5	15.09ID 242.9	12.70ID 247.6	28.58ID 215.9	25.40ID 222.3
12	300	323.8	Not listed	10.31ID 303.2	9.52ID 304.8	17.48ID 288.9	12.70ID 298.5	33.32ID 257.2	25.40ID 273.1
14	350	355.6	6.35ID 342.9	11.13ID 333.3	9.52ID 336.5	19.05ID 317.5	12.70ID 330.2	35.71ID 284.2	Not listed
16	400	406.4	6.35ID 393.7	12.70ID 381.0	9.52ID 387.3	21.44ID 363.5	12.70ID 381.0	40.49ID 325.4	Not listed
18	450	457.2	6.35ID 444.5	14.27ID 428.7	9.52ID 438.2	23.83ID 409.5	12.70ID 431.8	45.24ID 366.7	Not listed
20	500	508.0	6.35ID 495.3	15.09ID 477.8	9.52ID 489.0	26.19ID 455.6	12.70ID 482.6	50.01ID 408.0	Not listed
22	550	558.8	6.35ID 546.1	Not listed	9.52ID 539.8	28.58ID 501.7	12.70ID 533.4	53.97ID 450.8	Not listed
24	600	609.6	6.35ID 596.9	17.48ID 574.6	9.52ID 590.6	30.96ID 547.7	12.70ID 584.2	59.54ID 490.5	Not listed

Stainless steel pipe (B36.19M), inches

ASME B36.19M stainless pipe walls in inches: Sch 5S, 10S, 40S and 80S with computed inside diameter
NPS	OD (in)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	0.405	Not listed	0.049ID 0.307	0.068ID 0.269	0.095ID 0.215
1/4	0.540	Not listed	0.065ID 0.410	0.088ID 0.364	0.119ID 0.302
3/8	0.675	Not listed	0.065ID 0.545	0.091ID 0.493	0.126ID 0.423
1/2	0.840	0.065ID 0.710	0.083ID 0.674	0.109ID 0.622	0.147ID 0.546
3/4	1.050	0.065ID 0.920	0.083ID 0.884	0.113ID 0.824	0.154ID 0.742
1	1.315	0.065ID 1.185	0.109ID 1.097	0.133ID 1.049	0.179ID 0.957
1-1/4	1.660	0.065ID 1.530	0.109ID 1.442	0.140ID 1.380	0.191ID 1.278
1-1/2	1.900	0.065ID 1.770	0.109ID 1.682	0.145ID 1.610	0.200ID 1.500
2	2.375	0.065ID 2.245	0.109ID 2.157	0.154ID 2.067	0.218ID 1.939
2-1/2	2.875	0.083ID 2.709	0.120ID 2.635	0.203ID 2.469	0.276ID 2.323
3	3.500	0.083ID 3.334	0.120ID 3.260	0.216ID 3.068	0.300ID 2.900
3-1/2	4.000	0.083ID 3.834	0.120ID 3.760	0.226ID 3.548	0.318ID 3.364
4	4.500	0.083ID 4.334	0.120ID 4.260	0.237ID 4.026	0.337ID 3.826
5	5.563	0.109ID 5.345	0.134ID 5.295	0.258ID 5.047	0.375ID 4.813
6	6.625	0.109ID 6.407	0.134ID 6.357	0.280ID 6.065	0.432ID 5.761
8	8.625	0.109ID 8.407	0.148ID 8.329	0.322ID 7.981	0.500ID 7.625
10	10.750	0.134ID 10.482	0.165ID 10.420	0.365ID 10.020	0.500ID 9.750
12	12.750	0.156ID 12.438	0.180ID 12.390	0.375ID 12.000	0.500ID 11.750
14	14.000	0.156ID 13.688	0.188ID 13.624	Not listed	Not listed
16	16.000	0.165ID 15.670	0.188ID 15.624	Not listed	Not listed
18	18.000	0.165ID 17.670	0.188ID 17.624	Not listed	Not listed
20	20.000	0.188ID 19.624	0.218ID 19.564	Not listed	Not listed
22	22.000	0.188ID 21.624	0.218ID 21.564	Not listed	Not listed
24	24.000	0.218ID 23.564	0.250ID 23.500	Not listed	Not listed

Show the same table in millimeters

ASME B36.19M stainless pipe walls in millimeters: Sch 5S, 10S, 40S and 80S with computed inside diameter
NPS	OD (mm)	Sch 5S	Sch 10S	Sch 40S	Sch 80S
1/8	10.3	Not listed	1.24ID 7.8	1.73ID 6.8	2.41ID 5.5
1/4	13.7	Not listed	1.65ID 10.4	2.24ID 9.2	3.02ID 7.7
3/8	17.1	Not listed	1.65ID 13.8	2.31ID 12.5	3.20ID 10.7
1/2	21.3	1.65ID 18.0	2.11ID 17.1	2.77ID 15.8	3.73ID 13.9
3/4	26.7	1.65ID 23.4	2.11ID 22.5	2.87ID 20.9	3.91ID 18.8
1	33.4	1.65ID 30.1	2.77ID 27.9	3.38ID 26.6	4.55ID 24.3
1-1/4	42.2	1.65ID 38.9	2.77ID 36.6	3.56ID 35.1	4.85ID 32.5
1-1/2	48.3	1.65ID 45.0	2.77ID 42.7	3.68ID 40.9	5.08ID 38.1
2	60.3	1.65ID 57.0	2.77ID 54.8	3.91ID 52.5	5.54ID 49.3
2-1/2	73.0	2.11ID 68.8	3.05ID 66.9	5.16ID 62.7	7.01ID 59.0
3	88.9	2.11ID 84.7	3.05ID 82.8	5.49ID 77.9	7.62ID 73.7
3-1/2	101.6	2.11ID 97.4	3.05ID 95.5	5.74ID 90.1	8.08ID 85.4
4	114.3	2.11ID 110.1	3.05ID 108.2	6.02ID 102.3	8.56ID 97.2
5	141.3	2.77ID 135.8	3.40ID 134.5	6.55ID 128.2	9.52ID 122.3
6	168.3	2.77ID 162.7	3.40ID 161.5	7.11ID 154.1	10.97ID 146.3
8	219.1	2.77ID 213.5	3.76ID 211.6	8.18ID 202.7	12.70ID 193.7
10	273.1	3.40ID 266.2	4.19ID 264.7	9.27ID 254.5	12.70ID 247.6
12	323.8	3.96ID 315.9	4.57ID 314.7	9.52ID 304.8	12.70ID 298.5
14	355.6	3.96ID 347.7	4.78ID 346.0	Not listed	Not listed
16	406.4	4.19ID 398.0	4.78ID 396.8	Not listed	Not listed
18	457.2	4.19ID 448.8	4.78ID 447.6	Not listed	Not listed
20	508.0	4.78ID 498.4	5.54ID 496.9	Not listed	Not listed
22	558.8	4.78ID 549.2	5.54ID 547.7	Not listed	Not listed
24	609.6	5.54ID 598.5	6.35ID 596.9	Not listed	Not listed

40S equals STD and 80S equals XS through NPS 12, so they match Sch 40 and Sch 80 up to NPS 10 and NPS 8 respectively; 40S and 80S are not shown above NPS 12.

Need pipe spools, weldments or machined fittings? , or read about welding.

Reading the chart

Inside diameter. The OD is fixed for each NPS, so ID = OD - 2 x wall. NPS 2 Sch 40: 2.375 - 2 x 0.154 = 2.067 in.

Weight. Plain-end carbon steel pipe weighs about 10.69 x (OD - wall) x wall lb/ft with dimensions in inches. NPS 2 Sch 40 works out to 3.66 lb/ft. Stainless is about 2 percent heavier. For other shapes use the metal weight calculator.

Pipe vs tube. Pipe is ordered by NPS and schedule; tube by actual OD and wall. A 1 in tube will not fit a 1 in pipe fitting. See tube and pipe sizes.

Tolerance. Pipe specs (ASTM A53, A106, A312) allow the wall to run under nominal (commonly 12.5 percent under for seamless and welded pipe). Pressure calculations use the minimum wall, not the nominal one in this chart.

Frequently asked questions

What does pipe schedule mean?

A schedule is a wall-thickness series. For a given NPS the outside diameter is fixed, so a higher schedule means a thicker wall and a smaller bore. The same schedule number is a thicker wall at a larger NPS: Sch 40 is 0.154 in at NPS 2 and 0.280 in at NPS 6.

Is Sch 40 the same as STD?

Through NPS 10, yes. From NPS 12 up, STD (standard weight) stays at 0.375 in while Sch 40 keeps getting thicker, so NPS 12 Sch 40 is 0.406 in but NPS 12 STD is 0.375 in. Likewise XS equals Sch 80 only through NPS 8 and stays at 0.500 in from NPS 10 up.

Why is 1 in pipe 1.315 in OD?

Nominal pipe size is a trade name, not a measurement. The outside diameter of each NPS was fixed long ago so threads and fittings fit every wall, and the name stayed close to the bore of the old standard-weight pipe. From NPS 14 up, the OD does equal the NPS.

What is the difference between Sch 10 and Sch 10S?

The S schedules (5S, 10S, 40S, 80S) come from ASME B36.19M for stainless pipe. B36.10M, the carbon and alloy steel standard, has its own Sch 10, which in the large sizes is heavier than 10S: at NPS 14 it is 0.250 in against 0.188 in for 10S. When a drawing says Sch 10, confirm which wall is meant.

What does DN mean?

Diametre nominal, the metric name for the same pipe. NPS 2 is DN 50, and its OD is still 60.3 mm. Like NPS, DN is a label, not the outside or inside diameter.