PVF Reference Library · Wall Charts

Pipe Schedule & Dimension Chart (NPS 1/8 to 12)

Outside diameter and nominal wall thickness for Schedule 10S, 40 and 80 pipe from NPS 1/8 through 12, with the sizes where stainless S schedules differ.

Ref PV-0049ASME B36.10MASME B36.19M

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

Pipe is ordered by Nominal Pipe Size (NPS) and schedule. For a given NPS, the outside diameter (OD) is fixed. The schedule sets the wall thickness, so a higher schedule means a thicker wall and a smaller inside diameter. ASME B36.10M covers welded and seamless wrought steel pipe. ASME B36.19M covers stainless steel pipe and adds the "S" schedules such as 10S, 40S and 80S.

How to read it

Find the NPS in the left column.
Read the OD. It is the same for every schedule.
Read across to the schedule for the nominal wall.
Inside diameter = OD − (2 × wall).

Dimensions (inches)

NPS	OD	Sch 10S wall	Sch 40 wall	Sch 80 wall
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	0.083	0.109	0.147
3/4	1.050	0.083	0.113	0.154
1	1.315	0.109	0.133	0.179
1-1/4	1.660	0.109	0.140	0.191
1-1/2	1.900	0.109	0.145	0.200
2	2.375	0.109	0.154	0.218
2-1/2	2.875	0.120	0.203	0.276
3	3.500	0.120	0.216	0.300
3-1/2	4.000	0.120	0.226	0.318
4	4.500	0.120	0.237	0.337
5	5.563	0.134	0.258	0.375
6	6.625	0.134	0.280	0.432
8	8.625	0.148	0.322	0.500
10	10.750	0.165	0.365	0.594
12	12.750	0.180	0.406	0.688

Key points

Through NPS 12, the OD is larger than the nominal size. From NPS 14 up, the OD equals the nominal size.
Sch 40S matches Sch 40 through NPS 10. At NPS 12, Sch 40S (and STD) is 0.375 in, thinner than Sch 40.
Sch 80S matches Sch 80 through NPS 8. At NPS 10 and 12, Sch 80S (and XS) is 0.500 in, thinner than Sch 80.
Walls are nominal. The pipe specification allows a mill tolerance below nominal.
Pressure ratings depend on material, temperature, joint type and code. Use the governing piping code, not this chart.

Common mistakes

Assuming 40S and 40 are the same at every size.
Ordering 10 or 12 in "XS" when the drawing says Sch 80.
Measuring the ID and calling it the size.
Using steel pipe ODs for copper tube or PVC tube sizes that follow different systems.

Governing standards: ASME B36.10M (welded and seamless wrought steel pipe); ASME B36.19M (stainless steel pipe).

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

More in Wall Charts

← All PVF sheets