Pipe Schedule Chart: SCH 5, 10, 20, 40, 80, 160 and XXS

Choosing a pipe by nominal size alone is not enough. A 2 inch pipe can have the same outside diameter but a very different wall thickness, inside diameter and weight depending on whether it is SCH 10S, SCH 40S, SCH 80S or SCH 160. That difference affects flow area, pressure design, welding, support loads, material cost and total shipping weight.

Metinox Overseas supplies stainless steel pipes, seamless pipes and welded pipes across multiple schedules and grades. This page brings schedule data into one central reference so engineers and buyers can move from technical selection to the correct product page without searching through separate grade pages.

What Does Pipe Schedule Mean?

Pipe schedule is a dimensionless designation used to group pipe wall thicknesses. It does not directly mean a pressure rating. For the same NPS, a higher schedule generally means a thicker wall and a smaller internal bore. The allowable pressure still depends on material grade, design temperature, corrosion allowance, manufacturing standard, joint efficiency and the piping code used for the project.

ASME B36.19M standardizes dimensions for welded and seamless wrought stainless steel pipe, while ASME B36.10M is widely used for wrought steel pipe dimensions. Stainless schedules often carry an “S” suffix, such as 10S, 40S and 80S. In procurement documents, always state the material specification as well as NPS and schedule, for example: ASTM A312 TP316L, NPS 2, SCH 40S, seamless, beveled ends.

NPS / DN Schedule Chart Schedule Comparison

NPS, DN and Outside Diameter Quick Reference

NPS (inch)	DN	Outside Diameter (mm)
1/2	15	21.34
3/4	20	26.67
1	25	33.40
1 1/4	32	42.16
1 1/2	40	48.26
2	50	60.33
2 1/2	65	73.03
3	80	88.90
4	100	114.30
5	125	141.30
6	150	168.28
8	200	219.08
10	250	273.05
12	300	323.85

NPS is a nominal designation, not a direct measurement of the outside diameter. For NPS 12 and below, the numerical NPS value is smaller than the actual outside diameter. This is why a schedule chart should be checked before calculating bore size, pipe weight or fitting compatibility.

Pipe Schedule Chart: Common Wall Thicknesses

NPS	OD mm	SCH 5S	SCH 10S	SCH 40S	SCH 80S	SCH 160	XXS
1/2	21.34	1.65	2.11	2.77	3.73	4.78	7.47
3/4	26.67	1.65	2.11	2.87	3.91	5.56	7.82
1	33.40	1.65	2.77	3.38	4.55	6.35	9.09
1 1/4	42.16	1.65	2.77	3.56	4.85	6.35	9.70
1 1/2	48.26	1.65	2.77	3.68	5.08	7.14	10.15
2	60.33	1.65	2.77	3.91	5.54	8.74	11.07
2 1/2	73.03	2.11	3.05	5.16	7.01	9.53	14.02
3	88.90	2.11	3.05	5.49	7.62	11.13	15.24
4	114.30	2.11	3.05	6.02	8.56	13.49	17.12
5	141.30	2.77	3.40	6.55	9.53	15.88	19.05
6	168.28	2.77	3.40	7.11	10.97	18.26	21.95
8	219.08	2.77	3.76	8.18	12.70	23.01	22.23
10	273.05	3.40	4.19	9.27	15.09	28.58	25.40
12	323.85	3.96	4.57	10.31	17.48	33.32	25.40

Wall thickness values are shown in millimetres. Schedule availability varies by NPS, material specification and manufacturing route. Some larger sizes do not follow a simple “higher schedule always equals thicker than every named class” pattern; for example, SCH 160 can exceed XXS in certain larger NPS ranges. The project specification should control final selection.

SCH 5S vs 10S vs 40S vs 80S vs 160

Schedule	Typical Character	Common Buying Context
SCH 5S	Very light wall	Low-pressure stainless process lines, drainage, selected hygienic or utility service where code permits
SCH 10S	Light wall	General stainless process piping, water, food, pharma and low-to-moderate pressure services
SCH 40S	Common standard wall	Broad industrial use where a stronger wall and common fitting availability are required
SCH 80S	Heavy wall	Higher mechanical duty, elevated design pressure or more demanding process service
SCH 160	Very heavy wall	High-pressure and critical service where the design code and material specification call for heavy wall
XXS	Extra-extra strong	Special heavy-wall applications; availability depends strongly on size and material

For stainless projects, schedule selection is only one part of the specification. Grade matters just as much. SS 304 pipe is widely used for general corrosion-resistant service. SS 316/316L pipe is commonly selected where chloride exposure or more aggressive process conditions are expected. SS 321/321H pipe is used in elevated-temperature service, while SS 904L pipe is considered for more aggressive chemical environments.

How to Read a Pipe Schedule in 4 Steps

1. Confirm the nominal pipe size, for example NPS 2 or DN 50.
2. Find the fixed outside diameter. NPS 2 has an OD of 60.33 mm.
3. Choose the required schedule. For NPS 2, SCH 10S is 2.77 mm wall, SCH 40S is 3.91 mm and SCH 80S is 5.54 mm.
4. Use OD minus two times the wall thickness to estimate the inside diameter, then verify tolerances and design requirements against the applicable standard and project specification.

Pipe Schedule, Weight and Price Are Connected

A thicker schedule increases metal cross-section and therefore increases weight per metre. That directly affects material value, freight, handling and support loads. When two quotations use the same grade and NPS but different schedules, comparing only the price per metre can be misleading. Convert both options to kg/m and confirm the actual wall thickness before comparing total cost.

The SS pipe weight chart provides theoretical kg/m and lb/ft values for common stainless sizes. Buyers comparing commercial options can then use the SS pipe price list to understand how grade, seamless versus welded construction, wall thickness and quantity affect the final quote.

Common Industries Using Scheduled Pipe

• Oil and gas process piping, utility lines and refinery systems.
• Chemical and petrochemical plants handling corrosive or temperature-sensitive media.
• Pharmaceutical, food and beverage systems that require corrosion resistance and controlled surface finish.
• Power generation, heat exchanger and boiler-related service.
• Marine, offshore, water treatment and desalination projects where material grade selection is critical.

Metinox Overseas also supplies matching pipe fittings and flanges so schedule, material grade and end connection can be coordinated across the piping system.

Frequently Asked Questions