3/4 inch pipe dimensions: OD and wall thickness by schedule
Deskely Completions team Singapore
A 3/4 inch pipe, NPS 3/4 or DN 20, has an outside diameter of 26.7 mm (1.050 inches) in every schedule. The nominal size is a name, not a measurement: the outside diameter is larger than 3/4 inch. The schedule sets the wall thickness, and with it the inside diameter and the weight.
The table gives every schedule listed for NPS 3/4 in ASME B36.10M and B36.19M, in mm and inches.
- Outside diameter: 26.7 mm (1.050 in), the same for every schedule.
- Schedule 40: 2.87 mm wall, 21.0 mm inside diameter.
- Schedule 80: 3.91 mm wall, 18.9 mm inside diameter.
- Metric equivalent: DN 20.
3/4 inch pipe dimensions by schedule
| Schedule | Wall mm (in) | ID mm (in) | kg/m (lb/ft) |
|---|---|---|---|
| Schedule 5S | 1.65 (0.065) | 23.40 (0.921) | 1.02 (0.68) |
| Schedule 10S | 2.11 (0.083) | 22.48 (0.885) | 1.28 (0.86) |
| Schedule 10 | 2.11 (0.083) | 22.48 (0.885) | 1.28 (0.86) |
| Schedule 30 | 2.41 (0.095) | 21.88 (0.861) | 1.44 (0.97) |
| STD (standard) | 2.87 (0.113) | 20.96 (0.825) | 1.69 (1.13) |
| Schedule 40 | 2.87 (0.113) | 20.96 (0.825) | 1.69 (1.13) |
| XS (extra strong) | 3.91 (0.154) | 18.88 (0.743) | 2.20 (1.48) |
| Schedule 80 | 3.91 (0.154) | 18.88 (0.743) | 2.20 (1.48) |
| Schedule 160 | 5.56 (0.219) | 15.58 (0.613) | 2.90 (1.95) |
| XXS (double extra strong) | 7.82 (0.308) | 11.06 (0.435) | 3.64 (2.45) |
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.
3/4 inch pipe outside diameter
The outside diameter of NPS 3/4 pipe is 26.7 mm, or 1.050 inches, whatever the schedule, so 3/4 inch fittings and flanges fit every wall thickness. In metric drawings and specifications the same size is called DN 20.
It is larger than 3/4 inch because, below NPS 14, the nominal size is a traditional name that once roughly matched the bore, not the outside.
Nearby sizes
- 1/2 inch pipe dimensions: OD 21.3 mm
- 1 inch pipe dimensions: OD 33.4 mm
Every size and schedule in one table: the pipe schedule chart.
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Frequently asked questions
What is the OD of 3/4 inch pipe?
26.7 mm (1.050 inches), the same for every schedule.
What is the wall thickness of 3/4 inch schedule 40 pipe?
2.87 mm (0.113 in), giving an inside diameter of 21.0 mm (0.825 in).
What is the wall thickness of 3/4 inch schedule 80 pipe?
3.91 mm (0.154 in), giving an inside diameter of 18.9 mm (0.743 in).
What is 3/4 inch pipe in DN?
DN 20.
How much does 3/4 inch schedule 40 pipe weigh?
1.69 kg/m (1.13 lb/ft) for plain-end carbon steel.
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