Nominal pipe size to outside diameter in inches
Type a value in NPS to get it in in OD instantly.
1.315in OD
That's about the same as a 1" gas line.
Convert the other way: in OD to NPS
What it means
How big is that pipe?
Steel pipe to ASME B36.10 / ISO 6708. The outside diameter is the same for every schedule; the wall, and so the bore, changes. Copper tube and PVC have their own sizes.
The math
How to convert NPS to in OD
Pipe sizes are a table: NPS 2 = DN 50 = 60.3 mm (2.375 in) OD, NPS 4 = DN 100 = 114.3 mm. From NPS 14 the OD equals the NPS in inches.
Example: 1 NPS = 1.315 in OD.
Every unit
That pipe in every system
Tables
NPS to in OD conversion table
| NPS | in OD |
|---|---|
| 1/8 NPS | 0.405 in OD |
| 1/4 NPS | 0.54 in OD |
| 3/8 NPS | 0.675 in OD |
| 1/2 NPS | 0.84 in OD |
| 3/4 NPS | 1.05 in OD |
| 1 NPS | 1.315 in OD |
| 1 1/4 NPS | 1.66 in OD |
| 1 1/2 NPS | 1.9 in OD |
| 2 NPS | 2.375 in OD |
| 2 1/2 NPS | 2.875 in OD |
| 3 NPS | 3.5 in OD |
| 4 NPS | 4.5 in OD |
| 5 NPS | 5.563 in OD |
| 6 NPS | 6.625 in OD |
| 8 NPS | 8.625 in OD |
| 10 NPS | 10.75 in OD |
| 12 NPS | 12.75 in OD |
| 14 NPS | 14 in OD |
| 16 NPS | 16 in OD |
| 18 NPS | 18 in OD |
| 20 NPS | 20 in OD |
| 24 NPS | 24 in OD |
in OD to NPS conversion table
| in OD | NPS |
|---|---|
| 0.405 in OD | 1/8 NPS |
| 0.54 in OD | 1/4 NPS |
| 0.675 in OD | 3/8 NPS |
| 0.84 in OD | 1/2 NPS |
| 1.05 in OD | 3/4 NPS |
| 1.32 in OD | ≈1 NPS |
| 1.66 in OD | 1 1/4 NPS |
| 1.9 in OD | 1 1/2 NPS |
| 2.38 in OD | ≈2 NPS |
| 2.88 in OD | ≈2 1/2 NPS |
| 3.5 in OD | 3 NPS |
| 4.5 in OD | 4 NPS |
| 5.56 in OD | ≈5 NPS |
| 6.62 in OD | ≈6 NPS |
| 8.63 in OD | ≈8 NPS |
| 10.8 in OD | ≈10 NPS |
| 12.8 in OD | ≈12 1/8 NPS |
| 14 in OD | 14 NPS |
| 16 in OD | 16 NPS |
| 18 in OD | 18 NPS |
| 20 in OD | 20 NPS |
| 24 in OD | 24 NPS |
Quick answers
Quick answers
- How many in OD is 1 NPS?
- 1 NPS is 1.315 in OD.
- How many in OD is 10 NPS?
- 10 NPS is 10.75 in OD.
The units
About these units
Nominal pipe size (NPS)
The US nominal size in inches: ½, 1, 2…
Outside diameter in inches (in OD)
The actual outside diameter in inches.
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