NPS 12 Pipe Dimensions
Outside diameter 12.750 in (323.8 mm) — fixed across every schedule. 14 wall thicknesses from ASME B36.10M, with bore, plain-end weight and flow area for each.
- Nominal size
- NPS 12
- Metric designator
- DN 300
- Outside diameter
- 12.750 in (323.8 mm)
- Schedules listed
- 14
- Standard weight wall
- 0.375 in (9.5 mm)
- Extra strong wall
- 0.500 in (12.7 mm)
Every schedule in NPS 12
Dimensions are given in inches, with the millimetre equivalent beneath in grey.
| Schedule | Wall thickness | Inside diameter | Weight, empty | Flow area (in²) | Water (US gal/ft) |
|---|---|---|---|---|---|
| Sch 5 | 0.1563.96 mm | 12.438315.93 mm | 20.9831.23 kg/m | 121.50 | 6.312 |
| Sch 10 | 0.1804.57 mm | 12.390314.71 mm | 24.1735.96 kg/m | 120.57 | 6.263 |
| Sch 20 | 0.2506.35 mm | 12.250311.15 mm | 33.3849.67 kg/m | 117.86 | 6.123 |
| Sch 30 | 0.3308.38 mm | 12.090307.09 mm | 43.7765.14 kg/m | 114.80 | 5.964 |
| Sch 40 | 0.40610.31 mm | 11.938303.23 mm | 53.5379.65 kg/m | 111.93 | 5.815 |
| STD | 0.3759.52 mm | 12.000304.80 mm | 49.5673.76 kg/m | 113.10 | 5.875 |
| Sch 60 | 0.56214.27 mm | 11.626295.30 mm | 73.16108.87 kg/m | 106.16 | 5.515 |
| Sch 80 | 0.68817.48 mm | 11.374288.90 mm | 88.63131.90 kg/m | 101.61 | 5.278 |
| XS | 0.50012.70 mm | 11.750298.45 mm | 65.4297.35 kg/m | 108.43 | 5.633 |
| Sch 100 | 0.84421.44 mm | 11.062280.97 mm | 107.32159.71 kg/m | 96.11 | 4.993 |
| Sch 120 | 1.00025.40 mm | 10.750273.05 mm | 125.49186.75 kg/m | 90.76 | 4.715 |
| Sch 140 | 1.12528.57 mm | 10.500266.70 mm | 139.68207.86 kg/m | 86.59 | 4.498 |
| Sch 160 | 1.31233.32 mm | 10.126257.20 mm | 160.27238.51 kg/m | 80.53 | 4.183 |
| XXS | 1.00025.40 mm | 10.750273.05 mm | 125.49186.75 kg/m | 90.76 | 4.715 |
Weight is calculated for carbon steel as w = 10.6802 × t × (OD − t) lb/ft and is the plain-end weight, excluding coatings, linings and fittings.
Standard weight does not coincide with any numbered schedule in this size. Extra strong does not coincide with a numbered schedule here.
This size, schedule by schedule
A page for each combination, with bore, weight, water capacity and the matching flange and fitting data.
This size in a schedule chart
Common questions
What is the outside diameter of NPS 12 pipe?
NPS 12 pipe has an outside diameter of 12.750 in (323.8 mm). That outside diameter is fixed: it is identical in every schedule, and only the wall thickness — and therefore the bore — changes from one schedule to the next.
How much does NPS 12 schedule 40 pipe weigh?
53.53 lb/ft (79.65 kg/m) as plain-end carbon steel, on a wall thickness of 0.406 in (10.3 mm).
What is the metric equivalent of NPS 12?
DN 300. DN is a dimensionless designator, not a measurement — DN 300 pipe does not measure 300 mm anywhere. Its actual outside diameter is 323.8 mm.