Schedule 40 pipe dimensions: OD, wall thickness, ID and weight
Deskely Completions team Singapore
Schedule 40 is the most common wall thickness for steel process, utility and water piping. Up to NPS 10 it is the same wall as STD (standard weight); from NPS 12 up it is thicker than STD.
The chart below gives every size in schedule 40, from NPS 1/8 to 36: outside diameter, wall thickness, inside diameter and the weight of plain-end carbon steel pipe, in mm and inches.
- Sch 40 is a wall thickness that changes with size: 3.91 mm on NPS 2, 6.02 mm on NPS 4.
- The outside diameter is fixed for each NPS, so a heavier schedule only changes the bore.
- Typical use: process and utility lines at moderate pressure.
- Weights are for plain-end carbon steel; stainless steel is about 2 percent heavier.
Schedule 40 pipe chart
Click a size for every schedule of that size. Dimensions are nominal, per ASME B36.10M.
| NPS | DN | OD mm (in) | Wall mm (in) | ID mm (in) | kg/m (lb/ft) |
|---|---|---|---|---|---|
| 1/8 | 6 | 10.3 (0.405) | 1.73 (0.068) | 6.84 (0.269) | 0.37 (0.25) |
| 1/4 | 8 | 13.7 (0.540) | 2.24 (0.088) | 9.22 (0.363) | 0.63 (0.43) |
| 3/8 | 10 | 17.1 (0.675) | 2.31 (0.091) | 12.48 (0.491) | 0.84 (0.57) |
| 1/2 | 15 | 21.3 (0.840) | 2.77 (0.109) | 15.76 (0.620) | 1.27 (0.85) |
| 3/4 | 20 | 26.7 (1.050) | 2.87 (0.113) | 20.96 (0.825) | 1.69 (1.13) |
| 1 | 25 | 33.4 (1.315) | 3.38 (0.133) | 26.64 (1.049) | 2.50 (1.68) |
| 1-1/4 | 32 | 42.2 (1.660) | 3.56 (0.140) | 35.08 (1.381) | 3.39 (2.28) |
| 1-1/2 | 40 | 48.3 (1.900) | 3.68 (0.145) | 40.94 (1.612) | 4.05 (2.72) |
| 2 | 50 | 60.3 (2.375) | 3.91 (0.154) | 52.48 (2.066) | 5.44 (3.65) |
| 2-1/2 | 65 | 73 (2.875) | 5.16 (0.203) | 62.68 (2.468) | 8.63 (5.80) |
| 3 | 80 | 88.9 (3.500) | 5.49 (0.216) | 77.92 (3.068) | 11.29 (7.59) |
| 3-1/2 | 90 | 101.6 (4.000) | 5.74 (0.226) | 90.12 (3.548) | 13.57 (9.12) |
| 4 | 100 | 114.3 (4.500) | 6.02 (0.237) | 102.26 (4.026) | 16.08 (10.80) |
| 5 | 125 | 141.3 (5.563) | 6.55 (0.258) | 128.20 (5.047) | 21.77 (14.63) |
| 6 | 150 | 168.3 (6.625) | 7.11 (0.280) | 154.08 (6.066) | 28.26 (18.99) |
| 8 | 200 | 219.1 (8.625) | 8.18 (0.322) | 202.74 (7.982) | 42.55 (28.59) |
| 10 | 250 | 273.1 (10.750) | 9.27 (0.365) | 254.56 (10.022) | 60.31 (40.53) |
| 12 | 300 | 323.8 (12.750) | 10.31 (0.406) | 303.18 (11.936) | 79.71 (53.56) |
| 14 | 350 | 355.6 (14.000) | 11.13 (0.438) | 333.34 (13.124) | 94.55 (63.54) |
| 16 | 400 | 406.4 (16.000) | 12.70 (0.500) | 381.00 (15.000) | 123.31 (82.86) |
| 18 | 450 | 457 (18.000) | 14.27 (0.562) | 428.46 (16.869) | 155.81 (104.70) |
| 20 | 500 | 508 (20.000) | 15.09 (0.594) | 477.82 (18.812) | 183.43 (123.26) |
| 24 | 600 | 610 (24.000) | 17.48 (0.688) | 575.04 (22.639) | 255.43 (171.64) |
| 32 | 800 | 813 (32.000) | 17.48 (0.688) | 778.04 (30.631) | 342.94 (230.44) |
| 34 | 850 | 864 (34.000) | 17.48 (0.688) | 829.04 (32.639) | 364.92 (245.22) |
| 36 | 900 | 914 (36.000) | 19.05 (0.750) | 875.90 (34.484) | 420.45 (282.53) |
Mill tolerances apply, and the pipe specification and purchase order for your project take precedence over this chart.
How to work out the inside diameter and weight
The inside diameter is the outside diameter minus twice the wall thickness. The weight per metre of plain-end carbon steel pipe is:
W (kg/m) = 0.0246615 x (OD - t) x t, with OD and wall thickness t in mm. For NPS 4 Sch 40: 0.0246615 x (114.3 - 6.02) x 6.02 = 16.08 kg/m.
Where Sch 40 pipe is used
Process and utility lines at moderate pressure, cooling water, compressed air, fire water and general plant piping.
Schedule 80 has a thicker wall at the same outside diameter, so it takes more pressure, weighs more and has a smaller bore.
Every schedule in one chart
To compare schedules side by side, or look up a size in any schedule, use the full pipe schedule chart. Other schedules:
The Deskely products for this
Frequently asked questions
What is the wall thickness of Sch 40 pipe?
It depends on the size. NPS 1/2: 2.77 mm, NPS 1: 3.38 mm, NPS 2: 3.91 mm, NPS 4: 6.02 mm, NPS 6: 7.11 mm, NPS 8: 8.18 mm, NPS 12: 10.31 mm. See the chart for every size.
What is the inside diameter of 2 inch Sch 40 pipe?
52.5 mm (2.066 in), from an outside diameter of 60.3 mm and a wall of 3.91 mm.
How much does 4 inch Sch 40 pipe weigh?
16.08 kg/m (10.80 lb/ft) for plain-end carbon steel.
How does Sch 40 compare with other schedules?
Schedule 80 has a thicker wall at the same outside diameter, so it takes more pressure, weighs more and has a smaller bore.
Is the outside diameter the same for every schedule?
Yes. For each NPS the outside diameter is fixed so that fittings and flanges fit; only the wall thickness and so the bore change with the schedule.
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