3/4" PVC and steel pipe are 1.050" (26.7 mm) across the outside. 3/4" copper, PEX and CTS CPVC are 0.875", which is 7/8" (22.2 mm).
3/4 inch pipe sizes by type
3/4" pipe and tube: outside diameter, inside diameter and wall | Pipe | Outside (OD) | Inside (ID) | Wall |
|---|
| PVC Schedule 40 | 1.050" (26.7 mm) | n/a | 0.113" |
|---|
| PVC Schedule 80 | 1.050" (26.7 mm) | n/a | 0.154" |
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| CPVC Schedule 80 (Charlotte Corzan) | 1.050" (26.7 mm) | n/a | 0.154" |
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| Steel Schedule 40, black or galvanized | 1.050" (26.7 mm) | 0.824" | 0.113" |
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| Steel Schedule 80 | 1.050" (26.7 mm) | 0.742" | 0.154" |
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| Copper Type K | 0.875" (22.2 mm) | 0.745" | 0.065" |
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| Copper Type L | 0.875" (22.2 mm) | 0.785" | 0.045" |
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| Copper Type M | 0.875" (22.2 mm) | 0.811" | 0.032" |
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| PEX (Uponor AquaPEX) | 0.875" (22.2 mm) | 0.671" | n/a |
|---|
| CTS CPVC (FlowGuard Gold) | 0.875" (22.2 mm) | n/a | 0.080" |
|---|
PVC and steel are made to iron pipe size and copper, PEX and CTS CPVC to copper tube size, so the same 3/4" label covers two widths. Within each group the outside stays put and the wall sets the inside: Schedule 80 PVC and steel are thicker than Schedule 40, and Type K copper is the thickest of the three copper types.
What fits a 3/4 inch pipe
- Copper, PEX and CTS CPVC: SharkBite’s 3/4" Max push-to-connect fittings are sized 3/4" CTS, for pipe 7/8" across, and SharkBite’s PEX guide says its push-to-connect fittings join copper, CTS CPVC and PEX in any combination.
- PEX clamps and hangers: for its PEX, Uponor says to use copper tube size supports and clamps whenever possible.
- Steel and PVC threads: 3/4" pipe thread is 1.050" across, the pipe’s own outside. A garden hose is almost the same width but has a different thread count, so it needs an adapter: see garden hose to 3/4" pipe.
- Joining two kinds: 3/4" PVC is wider than 3/4" copper or PEX, so it takes a transition fitting. See connecting different pipe.
Measuring your pipe
To measure it and tell it from 1/2" pipe, see how to tell pipe size.
Common questions
What is the inside diameter of 3/4 inch copper pipe?
It depends on the type: 0.745" for Type K, 0.785" for Type L and 0.811" for Type M, in the Copper Development Association's tables. All three are 0.875" outside.
Is 3/4 inch PVC the same size as 3/4 inch steel pipe?
On the outside, yes: both are 1.050". Wheatland Tube's Schedule 40 steel has a 0.113" wall and a 0.824" inside, and Charlotte Pipe's Schedule 40 PVC has a 0.113" minimum wall.
How big is 3/4 inch PEX inside?
Uponor AquaPEX is 0.671" inside and 0.875" outside. Other makers' PEX shares the outside size, since PEX is copper tube size; check the maker's sheet for its inside.
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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 Max Installation Guide (2023): approved pipe, depths, removal, burial, warnings
- 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.