1/2" PVC and steel pipe are 0.840" (21.3 mm) across the outside. 1/2" copper, PEX and CTS CPVC are 0.625", which is 5/8" (15.9 mm).
1/2 inch pipe sizes by type
1/2" pipe and tube: outside diameter, inside diameter and wall | Pipe | Outside (OD) | Inside (ID) | Wall |
|---|
| PVC Schedule 40 | 0.840" (21.3 mm) | n/a | 0.109" |
|---|
| PVC Schedule 80 | 0.840" (21.3 mm) | n/a | 0.147" |
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| CPVC Schedule 80 (Charlotte Corzan) | 0.840" (21.3 mm) | n/a | 0.147" |
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| Steel Schedule 40, black or galvanized | 0.840" (21.3 mm) | 0.622" | 0.109" |
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| Steel Schedule 80 | 0.840" (21.3 mm) | 0.549" | 0.147" |
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| Copper Type K | 0.625" (15.9 mm) | 0.527" | 0.049" |
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| Copper Type L | 0.625" (15.9 mm) | 0.545" | 0.040" |
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| Copper Type M | 0.625" (15.9 mm) | 0.569" | 0.028" |
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| PEX (Uponor AquaPEX) | 0.625" (15.9 mm) | 0.475" | n/a |
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| CTS CPVC (FlowGuard Gold) | 0.625" (15.9 mm) | n/a | 0.068" |
|---|
Two sizing systems share the 1/2" name. PVC and steel are iron pipe size, where Schedule 40 and Schedule 80 have the same outside and a thicker wall on 80. Copper, PEX and CTS CPVC are copper tube size, and the copper types differ only on the inside.
What fits a 1/2 inch pipe
- Copper, PEX and CTS CPVC: SharkBite sizes its 1/2" push-to-connect fittings 1/2" CTS, for pipe 5/8" across, and they take copper, CTS CPVC and PEX in any combination. Copper Types K, L and M of one size have the same outside; only the wall differs.
- PEX clamps and hangers: for its PEX, Uponor says to use copper tube size supports and clamps whenever possible.
- PVC and steel: 1/2" pipe thread is cut on the same 0.840" outside, so threaded 1/2" steel pipe takes 1/2" pipe thread fittings. See pipe thread size.
- PVC to copper or PEX: the PVC is wider, so a fitting for one doesn’t slip onto the other. See PVC to copper and PEX to PVC.
Measuring your pipe
Hold a tape or caliper across the end of the pipe at its widest point. At 1/2" the two systems are about 0.2" apart, so a tape tells them apart. For the coin check and the 3/4" sizes, see how to tell pipe size.
Common questions
Is 1/2 inch PEX the same outside diameter as 1/2 inch copper?
Yes. Both are copper tube size, 0.625" (5/8") across. Uponor AquaPEX has a smaller inside, 0.475", than Type L copper's 0.545", because its wall is thicker.
What is the inside diameter of 1/2 inch Schedule 40 steel pipe?
0.622" in Wheatland Tube's table, with a 0.109" wall. Schedule 80 is 0.549" inside with a 0.147" wall. Both are 0.840" outside.
Why does my 1/2 inch pipe measure a little off?
The tables give average or nominal sizes, not exact ones. Wheatland allows the outside of its steel pipe from 1/2" to 1-1/2" to be up to 1/64" over or under.
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Where we get our information from
The sizes come from the pipe makers’ own tables (Charlotte Pipe, Wheatland Tube, Uponor) and the Copper Development Association’s tube tables; the fitting sizes from SharkBite’s installation guides. Checked against published data from Uponor, SharkBite, National Bureau of Standards, Charlotte Pipe and Copper Development Association (plus 1 more).
See all 9 sources
- National Bureau of Standards, Handbook H28 (1957) Part II: Table VII.2 (American Standard taper pipe threads, NPT) and Tables X.1–X.3 (hose coupling threads, NH)
- 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
- Charlotte Pipe, Plastics Technical Manual (2026), product data: average outside diameter and minimum wall of PVC Schedule 40 and 80, PVC DWV, PVC and ABS foam core, 4" sewer and drain pipe, and CTS CPVC
- 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"
- Wheatland Tube, Standard Pipe (SureThread and ERW) brochure: ASTM A53 Schedule 40 and 80 outside diameter, inside diameter and wall, black and galvanized, ASME B36.10M
General guidance from manufacturer and standards data. Parts vary by brand, so check the size printed on the package against what you measured. For gas lines or anything inside a wall, use a licensed plumber.