Pipe dimensions
Different ways to designate pipe outer diameter and wall thickness
Nominal pipe size (NPS) indicates outer diameter
- NPS 1/2: 0.840” outer diameter
- Larger outer diameter have larger NPS designation
- NPS designations run from 1/8 to 40
Schedule indicates wall thickness
- Schedule 10S for NPS 1: 0.083” wall
- Larger wall thickness for larger schedule designation
| NPS Designation | Outside diameter (inches) | Schedule 10S wall thickness (inches) | Schedule 40S wall thickness (inches) |
| ½ | 0.840 | 0.083 | 0.109 |
| 1 | 1.315 | 0.109 | 0.133 |
| 2 | 2.375 | 0.109 | 0.154 |
| 4 | 4.50 | 0.120 | 0.237 |