PEX is copper tube size, so 1/2" PEX is 0.625" (5/8", 15.9 mm) across, the same as 1/2" copper. Its thicker wall leaves 1/2" PEX about 0.475" (12.1 mm) inside in SharkBite’s and Uponor’s tables.
PEX pipe size chart
PEX tubing (copper tube size): outside diameter, wall and inside diameter | Size | Outside (OD) | Wall | Inside (ID) |
|---|
| 1/4" | 0.375" (9.5 mm) | 0.062" | 0.241" (6.1 mm) |
|---|
| 3/8" | 0.500" (12.7 mm) | 0.070" | 0.350" (8.9 mm) |
|---|
| 1/2" | 0.625" (15.9 mm) | 0.070" | 0.475" (12.1 mm) |
|---|
| 3/4" | 0.875" (22.2 mm) | 0.097" | 0.671" (17.0 mm) |
|---|
| 1" | 1.125" (28.6 mm) | 0.125" | 0.862" (21.9 mm) |
|---|
| 1-1/4" | 1.375" (34.9 mm) | 0.153" | 1.054" (26.8 mm) |
|---|
| 1-1/2" | 1.625" (41.3 mm) | 0.181" | 1.244" (31.6 mm) |
|---|
| 2" | 2.125" (54.0 mm) | 0.236" | 1.629" (41.4 mm) |
|---|
| 2-1/2" | 2.625" (66.7 mm) | n/a | 2.011" (51.1 mm) |
|---|
| 3" | 3.125" (79.4 mm) | n/a | 2.398" (60.9 mm) |
|---|
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PEX-a and PEX-b
SharkBite’s PEX-a and PEX-b tubing list the same outside, wall and inside at 1/2", 3/4" and 1", the sizes both of its sheets cover. Uponor’s AquaPEX, a PEX-a pipe, has the same outside and inside from 1/2" to 2".
SharkBite’s sheets give an unsupported bend radius of 6 times the outside diameter for its PEX-a and 8 times for its PEX-b. For 1/2" tubing that’s a radius of about 3-3/4" and 5".
Fittings for PEX
- Push-to-connect: SharkBite sizes its fittings by copper tube size, so a 1/2" fitting takes 1/2" PEX, copper or CTS CPVC. See SharkBite fittings.
- Expansion: Uponor’s ProPEX fittings are made for its PEX from 3/8" through 3".
- Joining other pipe: PEX and copper of one size have the same outside. For PVC, which is wider, see the PVC pipe size chart and PEX to PVC.
Measuring PEX
Measure across the outside with a caliper and match it to the chart. PEX and copper of the same size measure alike, so look at the material too. See how to tell pipe size and the copper pipe size chart.
Common questions
What is the inside diameter of 3/4 inch PEX?
0.671 inch (17.0 mm) in SharkBite's and Uponor's tables, with a 0.875 inch outside.
How thick is the wall of 1 inch PEX?
At least 0.125 inch, plus up to 0.013 inch, on SharkBite's sheets. That leaves 1 inch PEX about 0.862 inch inside.
Is 3/8 inch PEX 3/8 inch across?
No. SharkBite's 3/8 inch PEX-b is 0.500 inch across the outside and about 0.35 inch inside.
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Where we get our information from
The sizes come from SharkBite’s PEX-a and PEX-b tubing spec sheets and Uponor’s AquaPEX submittal, which agree wherever they list the same size, and the copper sizes from the Copper Development Association. Checked against published data from SharkBite, Uponor and Copper Development Association.
See all 8 sources
- Uponor, Plumbing Design Assistance Manual (PEX is copper tube size)
- SharkBite (Reliance Worldwide), SharkBite Installation Guide (2020): pipe insertion depth table, integral PEX stiffener
- SharkBite (Reliance Worldwide), SharkBite PEX Installation Guide (2021): fits copper, CTS CPVC and PEX in any combination
- Uponor, PEX Piping Systems Installation Guide, seventh edition (2025): ProPEX expansion fittings, pipe colors, copper and threaded adapters, no soldering within 18" of PEX
- Copper Development Association, The Copper Tube Handbook (2026), Tables 14.2a-d: outside diameter, inside diameter and wall of Type K, L, M and DWV tube; outside diameter 1/8" over the standard size
- Uponor, Uponor AquaPEX white straight lengths submittal (2026): inner and outer diameter, 1/2" to 3"
- SharkBite (RWC), PEX-b Tubing specification sheet, Rev 4.0 (07-15-26): outside diameter and tolerance, wall, approximate inside diameter, 1/4" to 1"; unsupported bend radius 8 x OD
- SharkBite (RWC), PEX-a Tubing specification sheet, Rev 5.0 (05-27-26): outside diameter and tolerance, wall, approximate inside diameter, 1/2" to 2"; unsupported bend radius 6 x OD
General guidance from manufacturer and standards data. Parts vary by brand, so check the size printed on the package against what you measured. This site doesn't cover gas lines. If in doubt about gas, call a licensed plumber or your local gas company.