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Pipe Diameter Calculator
Calculate minimum pipe wall thickness per ASME B31.3
Input Parameters
Typical: Carbon steel ~122 MPa (17.7 ksi)
Range 0.6–1.0 | Seamless=1.0, Welded=0.85
Common Pipe Schedule Wall Thickness
| DN | NPS | Sch 10 | Sch 40 | Sch 80 | Sch 160 |
|---|---|---|---|---|---|
| 15 | 1/2" | 1.65 | 2.77 | 3.73 | 7.47 |
| 20 | 3/4" | 1.65 | 2.87 | 3.91 | 7.82 |
| 25 | 1" | 1.65 | 3.38 | 4.55 | 9.09 |
| 32 | 1¼" | 1.65 | 3.56 | 5.08 | 10.29 |
| 40 | 1½" | 1.65 | 3.68 | 5.08 | 11.13 |
| 50 | 2" | 1.65 | 3.91 | 5.54 | 11.07 |
| 65 | 2½" | 2.11 | 5.16 | 7.01 | 14.02 |
| 80 | 3" | 2.11 | 5.49 | 7.62 | 15.24 |
| 100 | 4" | 2.11 | 6.02 | 8.56 | 17.12 |
| 125 | 5" | 2.77 | 6.55 | 9.53 | 19.05 |
| 150 | 6" | 2.77 | 7.11 | 10.97 | 21.95 |
| 200 | 8" | 2.77 | 8.18 | 12.7 | 22.23 |
| 250 | 10" | 3.4 | 9.27 | 12.7 | 25.4 |
| 300 | 12" | 3.96 | 10.31 | 14.27 | 33.32 |
| 350 | 14" | 3.96 | 11.13 | 15.88 | 35.71 |
| 400 | 16" | 4.19 | 12.7 | 16.66 | 40.49 |
| 450 | 18" | 4.19 | 14.27 | 19.05 | 45.24 |
| 500 | 20" | 4.78 | 15.09 | 20.62 | 50.01 |
| 600 | 24" | 5.54 | 17.48 | 24.61 | 59.54 |
Wall thickness in mm | Full schedules: Sch 10/20/30/40/60/80/100/120/140/160
Formula Reference (ASME B31.3)
Straight Pipe Wall Thickness:
t = P × D / (2 × (S × E + P × Y))
t = wall thickness | P = design pressure | D = outside diameter | S = allowable stress | E = joint efficiency | Y = coefficient (typ. 0.4)