Building materials · Reference
Standard PVC pipe is sized by nominal size (NPS), not actual diameter — a 1 in pipe has a 1.315 in (33.4 mm) OD. Schedule 40 and 80 share the same OD; Sch 80 adds wall thickness for higher pressure.
PVC pipe is specified by nominal size (NPS); the outside diameter is fixed while the schedule (wall thickness) sets the inside diameter.
| Nominal size (NPS) | Outside diameter (OD) | Wall thickness (min) | Average inside diameter |
|---|---|---|---|
| 1/2 in | 0.840 in (21.3 mm) | 0.109 in (2.77 mm) | 0.602 in (15.3 mm) |
| 3/4 in | 1.050 in (26.7 mm) | 0.113 in (2.87 mm) | 0.804 in (20.4 mm) |
| 1 in | 1.315 in (33.4 mm) | 0.133 in (3.38 mm) | 1.029 in (26.1 mm) |
| 1-1/2 in | 1.900 in (48.3 mm) | 0.145 in (3.68 mm) | 1.590 in (40.4 mm) |
| 2 in | 2.375 in (60.3 mm) | 0.154 in (3.91 mm) | 2.047 in (52.0 mm) |
| 3 in | 3.500 in (88.9 mm) | 0.216 in (5.49 mm) | 3.042 in (77.3 mm) |
| 4 in | 4.500 in (114.3 mm) | 0.237 in (6.02 mm) | 3.998 in (101.6 mm) |
| 6 in | 6.625 in (168.3 mm) | 0.280 in (7.11 mm) | 6.031 in (153.2 mm) |
Source: Piping-World — PVC Sch 40 dimensions per ASTM D1785 (2021)
| Nominal size (NPS) | Outside diameter (OD) | Wall thickness (min) | Average inside diameter |
|---|---|---|---|
| 1/2 in | 0.840 in (21.3 mm) | 0.147 in (3.73 mm) | 0.526 in (13.4 mm) |
| 3/4 in | 1.050 in (26.7 mm) | 0.154 in (3.91 mm) | 0.722 in (18.3 mm) |
| 1 in | 1.315 in (33.4 mm) | 0.179 in (4.55 mm) | 0.936 in (23.8 mm) |
| 1-1/2 in | 1.900 in (48.3 mm) | 0.200 in (5.08 mm) | 1.476 in (37.5 mm) |
| 2 in | 2.375 in (60.3 mm) | 0.218 in (5.54 mm) | 1.913 in (48.6 mm) |
| 3 in | 3.500 in (88.9 mm) | 0.300 in (7.62 mm) | 2.864 in (72.8 mm) |
| 4 in | 4.500 in (114.3 mm) | 0.337 in (8.56 mm) | 3.786 in (96.2 mm) |
| 6 in | 6.625 in (168.3 mm) | 0.432 in (10.97 mm) | 5.709 in (145.0 mm) |
Source: Piping-World — PVC Sch 80 dimensions per ASTM D1785 (2021)
| Nominal outside diameter | PN10 wall (SDR 21) | PN16 wall (SDR 13.6) | Typical use |
|---|---|---|---|
| Ø20 mm (0.79 in) | — | 1.5 mm (0.059 in) | Small supply / irrigation |
| Ø25 mm (0.98 in) | — | 1.9 mm (0.075 in) | Supply lines |
| Ø32 mm (1.26 in) | 1.6 mm (0.063 in) | 2.4 mm (0.094 in) | Distribution |
| Ø40 mm (1.57 in) | 1.9 mm (0.075 in) | 3.0 mm (0.118 in) | Distribution |
| Ø50 mm (1.97 in) | 2.4 mm (0.094 in) | 3.7 mm (0.146 in) | Mains |
| Ø63 mm (2.48 in) | 3.0 mm (0.118 in) | 4.7 mm (0.185 in) | Mains |
| Ø110 mm (4.33 in) | 4.2 mm (0.165 in) | 6.6 mm (0.260 in) | Buried water main |
Source: National Plastic — Pressure Pipe System (EN ISO 1452-2:2009) (2009)
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No. NPS is a nominal label, not a measured size. A 1 in PVC pipe has an outside diameter of 1.315 in (33.4 mm) and a Schedule 40 inside diameter of about 1.029 in (26.1 mm).
They share the same outside diameter, but Schedule 80 has thicker walls (e.g., 0.218 vs 0.154 in at 2 in). That gives Sch 80 a higher pressure rating and a smaller inside diameter, so slightly less flow.
2 in NPS PVC has a 2.375 in (60.3 mm) outside diameter in both Schedule 40 and Schedule 80 per ASTM D1785.
Metric PVC-U (ISO 161 / EN ISO 1452) is sized by actual OD in mm: Ø20, 25, 32, 40, 50, 63, 110 mm, and rated by pressure class PN (bar) rather than schedule.
No. Within one nominal size, Schedule 40, 80 and 120 all have the same OD. Only the wall thickness and inside diameter change, so fittings for a given size fit any schedule.
Every figure on this page is traced to a named source, linked under each table. Standard sizes come from published standards and established industry references; where a size is a typical range or varies by manufacturer, we say so. Sizes vary by region, model and revision — treat these as the standard reference, and confirm the exact spec of the item you are selling.
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