PEX Tubing Size Chart
Quick answer: PEX tubing is usually sold by nominal CTS size, not by inside diameter. For example, 1/2 in PEX has about 0.625 in outside diameter, and 3/4 in PEX has about 0.875 in outside diameter. The inside diameter depends on the wall thickness and the exact standard.
PEX Tubing Size Chart
| Nominal PEX size | Average OD | Minimum wall | Approx. ID | Common use |
|---|---|---|---|---|
| 3/8 in | 0.500 in / 12.7 mm | 0.070 in / 1.78 mm | 0.350 in | Small fixture runs |
| 1/2 in | 0.625 in / 15.9 mm | 0.070 in / 1.78 mm | 0.475 in | Common fixture branches |
| 5/8 in | 0.750 in / 19.1 mm | 0.083 in / 2.11 mm | 0.574 in | Radiant and specialty runs |
| 3/4 in | 0.875 in / 22.2 mm | 0.097 in / 2.46 mm | 0.671 in | Large branches/small trunk |
| 1 in | 1.125 in / 28.6 mm | 0.125 in / 3.18 mm | 0.863 in | Main distribution |
| 1-1/4 in | 1.375 in / 34.9 mm | 0.153 in / 3.89 mm | 1.054 in | Large distribution |
| 1-1/2 in | 1.625 in / 41.3 mm | 0.181 in / 4.60 mm | 1.244 in | Large distribution |
| 2 in | 2.125 in / 54.0 mm | 0.236 in / 5.99 mm | 1.629 in | Large distribution |
PEX Sizing Notes
- PEX, copper, and CPVC CTS sizes share similar outside diameters for compatible push fittings.
- Expansion, crimp, clamp, and push-fit systems use different fittings and instructions.
- Check pressure-temperature rating, oxygen barrier needs, bend radius, and local plumbing code.
- For flow planning, count fitting restrictions as well as tubing length.
Related references: pipe size chart in mm and inches and PVC pipe sizes chart.
Source Notes
Dimensions were checked against ASTM F876-style PEX references including Plastic Pipe Institute PEX data, PEX Universe technical specifications, and Viega PureFlow PEX tubing data. Verify the product submittal for engineered work.
