1/2 inch pipe dimensions: OD and wall thickness by schedule
Deskely Completions team Singapore
A 1/2 inch pipe, NPS 1/2 or DN 15, has an outside diameter of 21.3 mm (0.840 inches) in every schedule. The nominal size is a name, not a measurement: the outside diameter is larger than 1/2 inch. The schedule sets the wall thickness, and with it the inside diameter and the weight.
The table gives every schedule listed for NPS 1/2 in ASME B36.10M and B36.19M, in mm and inches.
- Outside diameter: 21.3 mm (0.840 in), the same for every schedule.
- Schedule 40: 2.77 mm wall, 15.8 mm inside diameter.
- Schedule 80: 3.73 mm wall, 13.8 mm inside diameter.
- Metric equivalent: DN 15.
1/2 inch pipe dimensions by schedule
| Schedule | Wall mm (in) | ID mm (in) | kg/m (lb/ft) |
|---|---|---|---|
| Schedule 5S | 1.65 (0.065) | 18.00 (0.709) | 0.80 (0.54) |
| Schedule 10S | 2.11 (0.083) | 17.08 (0.672) | 1.00 (0.67) |
| Schedule 10 | 2.11 (0.083) | 17.08 (0.672) | 1.00 (0.67) |
| Schedule 30 | 2.41 (0.095) | 16.48 (0.649) | 1.12 (0.75) |
| STD (standard) | 2.77 (0.109) | 15.76 (0.620) | 1.27 (0.85) |
| Schedule 40 | 2.77 (0.109) | 15.76 (0.620) | 1.27 (0.85) |
| XS (extra strong) | 3.73 (0.147) | 13.84 (0.545) | 1.62 (1.09) |
| Schedule 80 | 3.73 (0.147) | 13.84 (0.545) | 1.62 (1.09) |
| Schedule 160 | 4.78 (0.188) | 11.74 (0.462) | 1.95 (1.31) |
| XXS (double extra strong) | 7.47 (0.294) | 6.36 (0.250) | 2.55 (1.71) |
Nominal dimensions. Weights are for plain-end carbon steel; stainless steel is about 2 percent heavier. Mill tolerances apply, and your project pipe specification takes precedence.
1/2 inch pipe outside diameter
The outside diameter of NPS 1/2 pipe is 21.3 mm, or 0.840 inches, whatever the schedule, so 1/2 inch fittings and flanges fit every wall thickness. In metric drawings and specifications the same size is called DN 15.
It is larger than 1/2 inch because, below NPS 14, the nominal size is a traditional name that once roughly matched the bore, not the outside.
Nearby sizes
- 3/8 inch pipe dimensions: OD 17.1 mm
- 3/4 inch pipe dimensions: OD 26.7 mm
Every size and schedule in one table: the pipe schedule chart.
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Frequently asked questions
What is the OD of 1/2 inch pipe?
21.3 mm (0.840 inches), the same for every schedule.
What is the wall thickness of 1/2 inch schedule 40 pipe?
2.77 mm (0.109 in), giving an inside diameter of 15.8 mm (0.620 in).
What is the wall thickness of 1/2 inch schedule 80 pipe?
3.73 mm (0.147 in), giving an inside diameter of 13.8 mm (0.545 in).
What is 1/2 inch pipe in DN?
DN 15.
How much does 1/2 inch schedule 40 pipe weigh?
1.27 kg/m (0.85 lb/ft) for plain-end carbon steel.
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