12 inch (DN 300) pipe dimensions & weight
12 inch (DN 300) steel pipe has an outside diameter of 323.9 mm (12.752 in) in every schedule. Below: wall thickness, inside diameter, weight per metre and water capacity for each ASME B36.10M / B36.19M schedule.
| Schedule | Wall (mm) | Wall (in) | ID (mm) | CS kg/m | CS lb/ft | SS 304 kg/m | Water L/m |
|---|---|---|---|---|---|---|---|
| Sch 5S | 3.96 | 0.156 | 315.98 | 31.24 | 20.99 | 31.56 | 78.42 |
| Sch 10S | 4.57 | 0.180 | 314.76 | 35.99 | 24.19 | 36.36 | 77.81 |
| Sch 20 | 6.35 | 0.250 | 311.20 | 49.73 | 33.42 | 50.24 | 76.06 |
| Sch 30 | 8.38 | 0.330 | 307.14 | 65.20 | 43.81 | 65.86 | 74.09 |
| STD | 9.53 | 0.375 | 304.84 | 73.88 | 49.65 | 74.63 | 72.99 |
| Sch 40 | 10.31 | 0.406 | 303.28 | 79.73 | 53.58 | 80.54 | 72.24 |
| Sch 60 | 14.27 | 0.562 | 295.36 | 108.96 | 73.22 | 110.07 | 68.52 |
| XS | 12.70 | 0.500 | 298.50 | 97.46 | 65.49 | 98.45 | 69.98 |
| Sch 80 | 17.48 | 0.688 | 288.94 | 132.08 | 88.76 | 133.43 | 65.57 |
| Sch 100 | 21.44 | 0.844 | 281.02 | 159.91 | 107.46 | 161.54 | 62.02 |
| Sch 120 | 25.40 | 1.000 | 273.10 | 186.97 | 125.64 | 188.88 | 58.58 |
| Sch 140 | 28.58 | 1.125 | 266.74 | 208.14 | 139.87 | 210.26 | 55.88 |
| Sch 160 | 33.32 | 1.312 | 257.26 | 238.76 | 160.45 | 241.19 | 51.98 |
| XXS | 25.40 | 1.000 | 273.10 | 186.97 | 125.64 | 188.88 | 58.58 |
CS = carbon steel (7.85 g/cm³). SS 304 at 7.93 g/cm³; for 316 multiply CS weight by 1.017. Water capacity = internal volume per metre.
Matching 12" flanges and fittings
| Class 150 flange | OD 485 mm · thk 30.2 mm · PCD 431.8 mm · 12 × 7/8" bolts |
| Class 300 flange | OD 520 mm · thk 49.3 mm · PCD 450.8 mm · 16 × 1-1/8" bolts |
| B16.9 fittings | 90° LR 457 mm · 45° LR 190 mm · 90° SR 305 mm · tee 254 mm · reducer 203 mm · cap 152 mm |
Full tables: Class 150 · Class 300 · B16.9 fittings.
Frequently asked questions
What is the OD of 12 inch pipe?
12 inch (DN 300) pipe has an outside diameter of 323.9 mm (12.752 in), regardless of schedule.
What is the wall thickness of 12 inch Schedule 40 pipe?
10.31 mm (0.406 in), giving an inside diameter of 303.28 mm.
How much does 12 inch Schedule 40 pipe weigh?
About 79.73 kg/m (53.58 lb/ft) in carbon steel, or 478.4 kg for a 6 m length.
What is the wall thickness of 12 inch Schedule 80 pipe?
17.48 mm, with an inside diameter of 288.94 mm and weight of 132.08 kg/m.
Last updated 2026-11-02