PVC Pipe Schedule to Dimensions and Pressure Converter
Convert PVC pipe nominal size and schedule to actual outer diameter, inner diameter, wall thickness, and maximum pressure rating.
Covers Schedule 40 and Schedule 80.
Select PVC pipe size and schedule — see all dimensions and pressure rating.
PVC pipe is sized by nominal pipe size (NPS), which does not correspond to any actual physical dimension of the pipe. The “schedule” number defines the wall thickness and pressure rating. Higher schedule numbers mean thicker walls and higher pressure capacity.
Understanding nominal pipe size: When you buy a “1-inch PVC pipe,” neither the inner diameter nor the outer diameter is actually 1 inch. The outer diameter of all schedule pipes of the same nominal size is identical — what changes between schedules is the wall thickness (and therefore the inner diameter). For example, 1-inch PVC pipe always has an OD of 1.315 inches, regardless of whether it is Schedule 40 or Schedule 80.
Schedule 40 vs Schedule 80:
Schedule 40 is the standard for most residential and light commercial plumbing, drainage, and irrigation. It has a lighter wall thickness and is less expensive. The white (or sometimes gray) color of Schedule 40 PVC is the most familiar type. Maximum working pressures range from about 810 PSI for 1/2-inch pipe down to about 160 PSI for 4-inch pipe. Pressure ratings decrease as pipe diameter increases because of the larger surface area the internal pressure acts upon.
Schedule 80 has a thicker wall, providing higher pressure ratings and greater impact resistance. It is gray or dark gray in color. Schedule 80 is used where pipes are exposed to physical damage, in chemical processing, or where higher pressures are needed. Maximum working pressures range from about 1130 PSI for 1/2-inch pipe down to about 230 PSI for 4-inch pipe. The inner diameter is smaller than Schedule 40 of the same nominal size, which slightly reduces flow capacity.
Key dimension relationships:
- Outer Diameter (OD) is the same for all schedules of a given nominal size
- Wall Thickness increases with higher schedule numbers
- Inner Diameter (ID) = OD - (2 x Wall Thickness)
- Higher schedule = thicker wall = smaller ID = higher pressure rating
Common PVC pipe dimensions:
| Nominal | OD (in) | Sch 40 Wall | Sch 40 ID | Sch 80 Wall | Sch 80 ID |
|---|---|---|---|---|---|
| 1/2 | 0.840 | 0.109 | 0.622 | 0.147 | 0.546 |
| 3/4 | 1.050 | 0.113 | 0.824 | 0.154 | 0.742 |
| 1 | 1.315 | 0.133 | 1.049 | 0.179 | 0.957 |
| 1-1/4 | 1.660 | 0.140 | 1.380 | 0.191 | 1.278 |
| 1-1/2 | 1.900 | 0.145 | 1.610 | 0.200 | 1.500 |
| 2 | 2.375 | 0.154 | 2.067 | 0.218 | 1.939 |
| 3 | 3.500 | 0.216 | 3.068 | 0.300 | 2.900 |
| 4 | 4.500 | 0.237 | 4.026 | 0.337 | 3.826 |
Temperature derating: PVC pressure ratings assume a maximum temperature of 73F (23C). As temperature increases, pressure capacity decreases dramatically:
- At 100F (38C): multiply rated pressure by 0.62
- At 120F (49C): multiply rated pressure by 0.40
- At 140F (60C): multiply rated pressure by 0.22
- PVC should never be used above 140F (60C) as it begins to soften
CPVC for hot water: For hot water applications (up to 200F / 93C), use CPVC (Chlorinated PVC) instead of standard PVC. CPVC pipe has the same sizing system but uses a cream or yellowish color to distinguish it from standard PVC.
Joining methods: PVC pipe is joined using solvent cement (PVC glue) which chemically welds the pipe and fitting together. Always use the correct primer and cement for your pipe type. Schedule 80 fittings can be used with Schedule 40 pipe, but not vice versa (the thinner Schedule 40 fittings may not handle the pressures that Schedule 80 pipe is rated for).