Selected Tubing Geometry
Interactive PEX Tubing Size and Dimension Lookup
The profile is proportional to the selected PPI average OD and calculated nominal ID, but it is not a full-size measuring template.
For the default 1/2-inch PEX, the PPI table lists a 0.625-inch average OD, 0.075-inch average wall, and 0.475-inch calculated nominal ID.
- Nominal size
- 1/2 in.
- Average OD
- 0.625 in.
- Average wall
- 0.075 in.
- Calculated nominal ID
- 0.475 in.
- Calculated bore area
- 0.177 in²
- Calculated volume
- 0.92 US gal/100 ft
- Typical empty weight
- 0.05 lb/ft
Dimension reference only
This chart does not approve a plumbing size. Flow demand, pressure loss, developed length, fittings, temperature, layout, product listing, adopted code, and manufacturer instructions can change the required size. Fitting bores may be smaller than the tubing ID.
Identify a size from measured OD
Complete Reference
PEX Tubing Dimensions by Nominal Size
North American CTS/NTS SDR9 PEX dimensions from PPI, with calculated bore geometry and unit conversion.
Search a nominal fraction, decimal size, OD, wall, ID, CTS, NTS, or SDR9. Choose “View” to load a row into the dimensioned profile.
No PEX sizes match this search. Try a nominal fraction such as 1/2, an OD such as 0.625, or clear the search.
Scroll horizontally to view additional columns and vertically to view additional rows. Column headers and the nominal-size column remain visible while scrolling.
| Identification | Dimensions | Calculated Geometry | Physical Reference | Actions | ||||
|---|---|---|---|---|---|---|---|---|
| Select | Copy | |||||||
| 1/4 in. | 0.375 in. | 0.067 in. | 0.241 in. | 0.046 in² | 0.24 US gal/100 ft | 0.03 lb/ft | ||
| 3/8 in. | 0.500 in. | 0.075 in. | 0.350 in. | 0.096 in² | 0.50 US gal/100 ft | 0.04 lb/ft | ||
| 1/2 in. | 0.625 in. | 0.075 in. | 0.475 in. | 0.177 in² | 0.92 US gal/100 ft | 0.05 lb/ft | ||
| 5/8 in. | 0.750 in. | 0.088 in. | 0.574 in. | 0.259 in² | 1.34 US gal/100 ft | 0.07 lb/ft | ||
| 3/4 in. | 0.875 in. | 0.102 in. | 0.671 in. | 0.354 in² | 1.84 US gal/100 ft | 0.10 lb/ft | ||
| 1 in. | 1.125 in. | 0.132 in. | 0.862 in. | 0.584 in² | 3.03 US gal/100 ft | 0.17 lb/ft | ||
| 1-1/4 in. | 1.375 in. | 0.161 in. | 1.054 in. | 0.873 in² | 4.53 US gal/100 ft | 0.25 lb/ft | ||
| 1-1/2 in. | 1.625 in. | 0.191 in. | 1.244 in. | 1.215 in² | 6.31 US gal/100 ft | 0.35 lb/ft | ||
| 2 in. | 2.125 in. | 0.248 in. | 1.629 in. | 2.084 in² | 10.83 US gal/100 ft | 0.60 lb/ft | ||
| 2-1/2 in. | 2.625 in. | 0.307 in. | 2.011 in. | 3.176 in² | 16.50 US gal/100 ft | 0.92 lb/ft | ||
| 3 in. | 3.125 in. | 0.363 in. | 2.399 in. | 4.520 in² | 23.48 US gal/100 ft | 1.29 lb/ft | ||
| 4 in. | 4.125 in. | 0.478 in. | 3.169 in. | 7.887 in² | 40.97 US gal/100 ft | 2.24 lb/ft | ||
PPI labels OD and wall as average values and ID as calculated. These are not manufacturing tolerance limits or guaranteed measurements for every product. Verify the tubing marking and current manufacturer literature. Full-table download is not offered because bulk redistribution rights were not verified.
How to Read the PEX Pipe Size Chart
- Nominal PEX size
- The trade designation used to select tubing and compatible systems. It is not the measured OD or ID.
- Average OD
- The PPI average outside diameter for North American CTS/NTS SDR9 tubing.
- Average wall
- The average radial thickness used in the PPI dimension table, not a minimum-wall tolerance.
- Calculated nominal ID
- PPI’s calculated bore diameter. Actual product measurements can vary within applicable tolerances.
- Calculated bore area
- Computed as π × ID² ÷ 4. Area is useful for geometry comparisons, not a stand-alone flow rating.
- Calculated volume
- Internal geometric capacity derived from the listed ID; it excludes fittings and installed-system effects.
- Typical empty weight
- PPI’s typical tubing weight. It is a reference value rather than a guaranteed shipping or design weight.
Nominal PEX Size vs. Actual OD and ID
North American PEX tubing is commonly sold in nominal tube sizes that follow a copper tube size outside-diameter basis. That is why a tube marked 1/2 inch has an average OD of 0.625 inch rather than 0.500 inch. The nominal label identifies the size family; it is not a direct measurement.
Inside diameter is smaller than outside diameter by twice the wall thickness. For the default row, 0.625 − 2(0.075) = 0.475 inch. PPI publishes calculated ID values, and small 0.001-inch differences can appear if someone recalculates from rounded displayed averages instead of the underlying dimensional basis.
Metric mode is a conversion, not DN. A displayed value such as 15.9 mm is the converted OD of 1/2-inch nominal PEX. It does not rename the tubing as DN 16 or establish interchangeability with a metric pipe standard.
Average Wall Thickness Is Not Minimum Wall Thickness
The controlling PPI web table describes its OD and wall entries as average values. Manufacturer technical sheets and standards-oriented product tables may instead present minimum wall thickness plus a tolerance. Those two bases answer different questions and should not be merged into one unlabeled column.
Use this page for a consistent PPI average-dimension reference. For acceptance inspection, purchasing, pressure rating, or product compliance, use the current standard, listing, and manufacturer data for the exact tubing being evaluated.
Worked PEX Dimension Examples
Identify a tube from 0.875-inch OD
Assumption: The tubing is believed to be within this North American CTS/NTS SDR9 PEX dataset.
The closest listed OD to 0.875 inch is exactly 0.875 inch, corresponding to nominal 3/4-inch PEX. This OD match does not prove material, wall, listing, or manufacturer.
Estimate volume in 50 ft of 1/2-inch PEX
Assumption: Use the 0.475-inch calculated nominal ID and ignore fittings.
Area = π(0.475²)/4 = 0.1772 in². Volume = 0.1772 × 600 ÷ 231 = about 0.46 US gallon. This geometric result does not determine allowable flow or installed system volume exactly.
Why Dimensions Alone Cannot Select a PEX Size
A dimension chart answers “what are the listed dimensions?” It cannot answer “what size should I install?” without a hydraulic and code basis. A plumbing design may need to account for:
- fixture demand, simultaneous use, and required flow at each outlet;
- available source pressure, elevation change, and minimum residual pressure;
- developed or equivalent length, valves, fittings, manifolds, and equipment losses;
- water temperature, allowable velocity, noise, and pressure-loss criteria;
- trunk-and-branch, home-run, or hybrid layout;
- the adopted plumbing code, product listing, and manufacturer instructions.
For a separate friction-loss calculation with justified inputs, use the Hazen-Williams Calculator. Use an appropriate actual ID and coefficient for the specific design basis; do not treat the dimension chart as approval of those inputs.
Do PEX-A, PEX-B, and PEX-C Use Different Sizes?
PEX-A, PEX-B, and PEX-C identify common crosslinking methods: peroxide, silane, and electron beam. PPI notes that the letters are not a quality-rating system. Compliant products made by different crosslinking methods can use the same CTS/NTS dimensional basis, so a crosslinking-method filter would not improve this dimension lookup.
The installation system can still differ. Joining method, fitting geometry, bend limits, tools, listings, and manufacturer requirements must match the actual product. Confirm the tubing print line and system literature rather than inferring compatibility from nominal size alone.
Tubing ID vs. Fitting Bore
The calculated ID in this chart describes the tubing bore, not the smallest passage through an installed fitting. Insert fittings occupy part of the tube opening and can create a smaller local passage. Expansion, press, push-connect, manifold, valve, and transition components use different geometries and loss characteristics.
For pressure-drop work, use manufacturer-specific fitting dimensions or equivalent-length/loss data for the chosen system. Do not substitute a tubing ID for a fitting bore, and do not assume two systems with the same nominal tubing size have identical hydraulic performance.
Source Scope, Limitations, and Related References
Dataset: PPI North American CTS/NTS SDR9 PEX tubing dimensions, nominal 1/4 through 4 inches. Source checked August 10, 2026.
The table uses the publicly displayed PPI dimension reference as its controlling data source. ASTM is cited for current public scope only; no ASTM table is reproduced. PPI OD, average wall, calculated ID, and typical weight remain source-labeled, while bore area and capacity are Turn2Engineering calculations from the published ID.
- Plastics Pipe Institute — PEX Pipe and TubingControlling 12-row CTS/NTS dimension table and notes defining average OD, average wall, calculated ID, typical weight, and typical volume.
- ASTM F876-26 — Crosslinked Polyethylene (PEX) TubingCurrent public standard scope reference. The copyrighted standard table is not reproduced.
- PPI PEX Plumbing Design and Installation Guide, Third Edition — Chapter 6Supports the explanation that system sizing depends on demand, pressure, temperature, length, layout, fittings, code, and product instructions.
- Viega PureFlow PEX Tubing Tech Data, TD-PF 0120Manufacturer-specific cross-check showing why minimum-wall/tolerance data must not be mislabeled as PPI average-wall data.
Dataset and Source-Check Details
- Publisher
- Turn2Engineering
- Source basis
- PPI CTS/NTS SDR9 dimension table
- Source-controlled fields
- Nominal size, average OD, average wall, calculated ID, typical weight
- Calculated fields
- Bore area and internal volume
- Canonical units
- Inches, square inches, US gallons per 100 ft, pounds per foot
- Metric display
- Converted mm, mm², L/100 m, and kg/m; not DN
- Excluded scope
- IPS/NPS, DN, composite tubing, fitting bores, pressure loss, flow rating, and manufacturer tolerances
- Rights/download decision
- Attributed educational display; no full CSV or bulk-table copy because redistribution rights were not verified
PEX Pipe Size Chart FAQs
The controlling PPI CTS/NTS table lists an average OD of 0.625 inch. The 1/2-inch label is a nominal trade designation, not the measured OD.
PEX is sold by a nominal CTS/NTS designation tied to a standardized outside-diameter system. Its inside diameter depends on wall thickness and is therefore smaller than the OD.
Corresponding North American CTS nominal sizes commonly share the same OD basis. Their wall thickness, ID, fittings, joining methods, material properties, and design requirements still differ.
No fixed multiplier applies to usable flow. The listed bore area increases from about 0.177 to 0.354 in², but actual flow depends on pressure, length, fittings, layout, temperature, criteria, and code.
No. It identifies dimensions. Installation sizing requires fixture demand, pressure-loss, length, fitting, temperature, layout, adopted-code, listing, and manufacturer checks.
Use the Nominal Size and Actual Dimensions for the Right Task
Use nominal size to identify the PEX size family, average OD for dimensional comparison or reverse lookup, average wall and calculated ID to understand the reference geometry, and manufacturer/code information for actual product acceptance and system design. Never substitute this chart for hydraulic sizing or assume a fitting bore equals the tubing ID.