12 inch Sch 40 pipe dimensions & weight
12 inch Sch 40 pipe (DN 300) — dimensions, weight and capacity per ASME B36.10M.
| Nominal size | 12" (DN 300) |
| Schedule | Sch 40 |
| Outside diameter | 323.9 mm (12.752 in) |
| Wall thickness | 10.31 mm (0.406 in) |
| Inside diameter | 303.28 mm (11.940 in) |
| Weight — carbon steel | 79.73 kg/m · 53.58 lb/ft |
| Weight — SS 304 / SS 316 | 80.54 / 81.05 kg/m |
| 6 m length (CS) | 478.4 kg |
| 20 ft length (CS) | 486.0 kg |
| Flow area | 722.40 cm² |
| Water capacity | 72.240 L/m |
| Outer surface (painting) | 1.0176 m²/m |
| Approx. max. working pressure* | 79 bar (1,140 psi) — A106 Gr B |
*Approximate ASME B31.3 straight-pipe rating at ≤ 38 °C for seamless A106 Gr B (S = 137.9 MPa, E = 1, 12.5% mill tolerance, no corrosion allowance). Use the wall thickness calculator for your own design conditions.
Other schedules for 12": Sch 10S · Sch 80 · Sch 160 · XXS · all 12" schedules
Frequently asked questions
What is the ID of 12 inch Sch 40 pipe?
303.28 mm (11.940 in), with OD 323.9 mm and wall 10.31 mm.
What is the weight of 12 inch Sch 40 pipe?
79.73 kg/m (53.58 lb/ft) in carbon steel; 478.4 kg per 6 m length.
What pressure can 12 inch Sch 40 pipe take?
Roughly 79 bar at ambient for seamless A106 Gr B under ASME B31.3 with no corrosion allowance; actual rating depends on material, temperature and code.
Last updated 2026-11-02