Pipe Schedule Chart — ASME B36.10M
OD, wall thickness, and ID for every nominal pipe size from 1/8" through 24", in every common schedule. Carbon and alloy steel pipe dimensions.
Standard Pipe Dimensions (Inches)
| NPS | OD | Sch 5 | Sch 10 | Sch 40 (Std) | Sch 80 (XS) | Sch 160 | XXS |
|---|---|---|---|---|---|---|---|
| 1/8" | 0.405 | — | 0.049 | 0.068 | 0.095 | — | — |
| 1/4" | 0.540 | 0.065 | 0.065 | 0.088 | 0.119 | — | — |
| 3/8" | 0.675 | 0.065 | 0.065 | 0.091 | 0.126 | — | — |
| 1/2" | 0.840 | 0.065 | 0.083 | 0.109 | 0.147 | 0.187 | 0.294 |
| 3/4" | 1.050 | 0.065 | 0.083 | 0.113 | 0.154 | 0.219 | 0.308 |
| 1" | 1.315 | 0.065 | 0.109 | 0.133 | 0.179 | 0.250 | 0.358 |
| 1-1/4" | 1.660 | 0.065 | 0.109 | 0.140 | 0.191 | 0.250 | 0.382 |
| 1-1/2" | 1.900 | 0.065 | 0.109 | 0.145 | 0.200 | 0.281 | 0.400 |
| 2" | 2.375 | 0.065 | 0.109 | 0.154 | 0.218 | 0.344 | 0.436 |
| 2-1/2" | 2.875 | 0.083 | 0.120 | 0.203 | 0.276 | 0.375 | 0.552 |
| 3" | 3.500 | 0.083 | 0.120 | 0.216 | 0.300 | 0.438 | 0.600 |
| 3-1/2" | 4.000 | 0.083 | 0.120 | 0.226 | 0.318 | — | — |
| 4" | 4.500 | 0.083 | 0.120 | 0.237 | 0.337 | 0.531 | 0.674 |
| 5" | 5.563 | 0.109 | 0.134 | 0.258 | 0.375 | 0.625 | 0.750 |
| 6" | 6.625 | 0.109 | 0.134 | 0.280 | 0.432 | 0.719 | 0.864 |
| 8" | 8.625 | 0.109 | 0.148 | 0.322 | 0.500 | 0.906 | 0.875 |
| 10" | 10.750 | 0.134 | 0.165 | 0.365 | 0.500 | 1.125 | — |
| 12" | 12.750 | 0.156 | 0.180 | 0.406 | 0.500 | 1.312 | — |
| 14" | 14.000 | 0.156 | 0.250 | 0.438 | 0.500 | 1.406 | — |
| 16" | 16.000 | 0.165 | 0.250 | 0.500 | 0.500 | 1.594 | — |
| 18" | 18.000 | 0.165 | 0.250 | 0.562 | 0.500 | 1.781 | — |
| 20" | 20.000 | 0.188 | 0.250 | 0.594 | 0.500 | 1.969 | — |
| 24" | 24.000 | 0.218 | 0.250 | 0.688 | 0.500 | 2.344 | — |
All wall thicknesses in inches. ID = OD − 2 × wall thickness. Standard (Std) and XS columns matchSchedule 40 and 80 through NPS 8"; above 8" they stay at 3/8" and 1/2" walls respectively. Per ASME B36.10M (carbon steel) — B36.19M tables differ slightly for stainless.
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How pipe schedules work
Nominal Pipe Size (NPS) is a tag, not a real measurement. NPS 2" pipe has an OD of 2.375" — the OD stays the same across every schedule for that nominal size. What changes between schedules is the wall thickness, which means the ID also changes. Heavier schedules have thicker walls and smaller IDs.
- Sch 5 / Sch 10: light wall, stainless tube applications, light-duty service
- Sch 40 (Std): the default for general carbon-steel pipe through NPS 10"
- Sch 80 (XS): extra strong, common for higher pressures and threaded service
- Sch 160: high-pressure / high-temperature service
- XXS: double extra strong, used where wall thickness is critical (oilfield, forged fittings)