SS304 Pipe Dimensions & Weight Chart: Complete ASME B36.19 Schedule 10S vs 40S Guide
2026-08-21
Introduction
When buying SS304 stainless steel pipes, one of the most important specifications is the pipe schedule.
Under ANSI/ASME B36.19M, stainless steel pipe dimensions are standardized by NPS size, outside diameter, wall thickness, and nominal weight. The “S” suffix distinguishes stainless steel schedules from carbon-steel pipe schedules under ASME B36.10M.
For B2B buyers, Schedule 10S and Schedule 40S are two of the most commonly requested specifications.
1. SS304 Schedule 10S vs 40S
The main difference is wall thickness.
For the same NPS size:
- Schedule 10S → thinner wall, lighter weight
- Schedule 40S → thicker wall, heavier weight
The outside diameter generally remains the same.
For example, an NPS 4 SS304 pipe has an outside diameter of 4.500 in (114.3 mm):
- 10S wall: 0.120 in (3.05 mm)
- 40S wall: 0.237 in (6.02 mm)
The corresponding theoretical weights are approximately 8.36 kg/m and 16.07 kg/m.
2. SS304 Pipe Dimensions & Theoretical Weight Chart
The following chart summarizes commonly purchased SS304 stainless steel pipe dimensions according to ASME B36.19M, showing Schedule 10S and 40S wall thickness and nominal plain-end weight.
| NPS | DN | OD（mm） | 10S Wall（mm） | 10S kg/m | 40S Wall（mm） | 40S kg/m |
| 1/8" | 6 | 10.3 | 1.24 | 0.28 | 1.73 | 0.37 |
| 1/4" | 8 | 13.7 | 1.65 | 0.49 | 2.24 | 0.63 |
| 3/8" | 10 | 17.1 | 1.65 | 0.63 | 2.31 | 0.85 |
| 1/2" | 15 | 21.3 | 2.11 | 1.00 | 2.77 | 1.27 |
| 3/4" | 20 | 26.7 | 2.11 | 1.28 | 2.87 | 1.68 |
| 1" | 25 | 33.4 | 2.77 | 2.09 | 3.38 | 2.5 |
| 1 1/4" | 32 | 42.2 | 2.77 | 2.69 | 3.56 | 3.39 |
| 1 1/2" | 40 | 48.3 | 2.77 | 3.11 | 3.68 | 4.05 |
| 2" | 50 | 60.3 | 2.77 | 3.93 | 3.91 | 5.44 |
| 2 1/2" | 65 | 73.0 | 3.05 | 5.26 | 5.16 | 8.63 |
| 3" | 80 | 88.9 | 3.05 | 6.45 | 5.49 | 11.29 |
| 3 1/2" | 90 | 101.6 | 3.05 | 7.40 | 5.74 | 13.57 |
| 4" | 100 | 114.3 | 3.05 | 8.36 | 6.02 | 16.07 |
| 5" | 125 | 141.3 | 3.40 | 11.57 | 6.55 | 21.77 |
| 6" | 150 | 168.3 | 3.40 | 13.84 | 7.11 | 28.26 |
| 8" | 200 | 219.1 | 3.76 | 19.96 | 8.18 | 42.55 |
| 10" | 250 | 273.1 | 4.19 | 27.78 | 9.27 | 60.31 |
| 12" | 300 | 323.9 | 4.57 | 36.00 | 9.53 | 73.88 |
The standard table covers additional NPS sizes beyond those shown above, including larger-diameter stainless steel pipe.
3. How Is Theoretical Pipe Weight Calculated?
Theoretical weight is based on the pipe's dimensions and stainless-steel density.
A simplified calculation is:
Weight ≈ π/4 × (OD² − ID²) × Density
where:
ID = OD − 2 × Wall Thickness
The values in the ASME table are nominal weights for plain-end pipe, so actual shipment weight can differ because of manufacturing tolerances, end finishing, and other factors.
For procurement, the standard nominal weight should therefore be used for quotation and theoretical weight calculations, while actual weighing should be used when verifying delivered cargo.
4. Which Should Buyers Choose: 10S or 40S?
Choose Schedule 10S when:
- Lower pipe weight is preferred
- Space and flow capacity are important
- The project specification permits thinner walls
- Cost optimization is required
Choose Schedule 40S when:
- A thicker wall is required
- Higher mechanical robustness is needed
- The project specification calls for 40S
- More demanding service conditions apply
However, Schedule 40S should not automatically be considered “better.” Pipe wall thickness should be selected according to pressure, temperature, corrosion allowance, mechanical requirements, and the applicable piping code.
5. What Should You Specify When Ordering SS304 Pipe?
To avoid misunderstandings with a supplier, a complete purchase specification should include:
- Material: SS304 / ASTM A312 TP304, where applicable
- Standard: ASME B36.19M
- NPS: e.g. 2", 4", 8"
- Schedule: 10S or 40S
- Outside diameter
- Wall thickness
- Pipe length
- Seamless or welded
- Surface finish
- MTC / inspection requirements
For example:
ASTM A312 TP304, ASME B36.19M, NPS 4", SCH 40S, OD 114.3 mm × WT 6.02 mm
This is much more precise than simply asking for a “4-inch SS304 pipe.”
Conclusion
For buyers sourcing SS304 stainless steel pipes, understanding the difference between Schedule 10S and Schedule 40S is essential for accurate quotation, weight calculation, and project specification.
Under ASME B36.19M, both schedules use standardized outside diameters, while their wall thicknesses and theoretical weights differ significantly.
For example, an NPS 4 pipe is 3.05 mm / 8.36 kg/m in 10S versus 6.02 mm / 16.07 kg/m in 40S.
The key is to specify NPS + OD + wall thickness + schedule + material grade + applicable standard when purchasing, rather than relying on the nominal pipe size alone.
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