What size hole saw for 1/2" copper or PEX?
1/2" copper pipe and 1/2" PEX are both 0.625" (5/8") across. Copper and PEX use copper tube size, where the outside diameter is the nominal size plus 1/8".
Here's the hole saw for passing them through a stud, joist or panel, with an easy-clearance size and an exact fit.
Nominal size
Change the size to compare. Under each, the pipe’s real outside diameter.
Hole saw for 1/2-inch copper or PEX pipe, by job
About 1/16" around the pipe, for movement and an imperfect cut.
Exactly the pipe’s 0.625" outside diameter: it can bind, and pipe at the top of its tolerance won’t go through.
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Nominal isn’t actual
Copper Types K, L and M all share the 0.625" outside diameter; only the wall thickness differs. PEX in copper tube size matches it.
Same trap as wood: lumber sizes, nominal vs actual.
Which one to use
Easy clearance leaves room for the pipe to move and for a slightly off-line cut. The exact fit is the smallest saw at least the pipe’s size; here it’s the same size as the pipe, so it can bind, and pipe at the top of its size tolerance won’t go through. In studs and joists, the code limits the hole by the lumber’s real depth: how big a hole you can drill in a stud. PEX through steel studs needs a grommet or sleeve.
Common questions
What size hole saw for 1/2 inch copper or PEX?
1/2" copper or PEX is 0.625" across, so use a 3/4" hole saw for easy clearance, or 5/8" for an exact fit (zero clearance: it can bind, or not pass pipe at the top of its tolerance).
Why can't I use a 1/2 inch hole saw for 1/2 inch copper or PEX?
Because the 1/2" is a nominal size, not a measurement. The pipe's real outside diameter is 0.625", bigger than a 1/2" hole.
Does PEX need a bigger hole than copper?
No: PEX is copper tube size, the same 0.625" across. Zurn says a hole at least 1/8" bigger than the tube needs no sleeve in wood (the 3/4" easy-clearance saw does that). In steel studs, use a grommet or sleeve.
Full hole saw chart
Hole saw size chart for pipe and conduit
| PVC / ABS | Actual OD | Easy clearance | Exact fit | Clear a coupling |
|---|---|---|---|---|
| 1/2" | 0.840"21.3 mm | 1"25.4 mm | 7/8"22.2 mm | 1-5/16"hub 1-3/32" |
| 3/4" | 1.050"26.7 mm | 1-3/16"30.2 mm | 1-1/16"27 mm | 1-7/16"hub 1-5/16" |
| 1" | 1.315"33.4 mm | 1-1/2"38.1 mm | 1-3/8"34.9 mm | 1-3/4"hub 1-5/8" |
| 1-1/4" | 1.660"42.2 mm | 1-13/16"46 mm | 1-11/16"42.9 mm | 2-1/8"hub 1-31/32" |
| 1-1/2" | 1.900"48.3 mm | 2-1/16"52.4 mm | 1-15/16"49.2 mm | 2-3/8"hub 2-7/32" |
| 2" | 2.375"60.3 mm | 2-1/2"63.5 mm | 2-3/8"zero clearance | 2-7/8"hub 2-3/4" |
| 2-1/2" | 2.875"73 mm | 3"76.2 mm | 2-7/8"zero clearance | 3-1/2"hub 3-11/32" |
| 3" | 3.500"88.9 mm | 3-5/8"92.1 mm | 3-1/2"zero clearance | 4-1/8"hub 4" |
| 4" | 4.500"114.3 mm | 4-5/8"117.5 mm | 4-1/2"zero clearance | 5-1/2"hub 5-1/32" |
| Copper / PEX | Actual OD | Easy clearance | Exact fit |
|---|---|---|---|
| 3/8" | 0.500"12.7 mm | 5/8"15.9 mm | 9/16"14.3 mm |
| 1/2" | 0.625"15.9 mm | 3/4"19 mm | 5/8"zero clearance |
| 3/4" | 0.875"22.2 mm | 1"25.4 mm | 7/8"zero clearance |
| 1" | 1.125"28.6 mm | 1-5/16"33.3 mm | 1-1/8"zero clearance |
| 1-1/4" | 1.375"34.9 mm | 1-1/2"38.1 mm | 1-3/8"zero clearance |
| 1-1/2" | 1.625"41.3 mm | 1-3/4"44.4 mm | 1-5/8"zero clearance |
| 2" | 2.125"54 mm | 2-1/4"57.2 mm | 2-1/8"zero clearance |
| Conduit | Into a box | Through, PVC / rigid | Through, EMT |
|---|---|---|---|
| 1/2" | 7/8"NEMA 0.875" | 1"exact 7/8" | 7/8"exact 3/4" |
| 3/4" | 1-1/8"NEMA 1.109" | 1-3/16"exact 1-1/16" | 1-1/16"exact 15/16" |
| 1" | 1-3/8"NEMA 1.375" | 1-1/2"exact 1-3/8" | 1-5/16"exact 1-3/16" |
| 1-1/4" | 1-3/4"NEMA 1.734" | 1-13/16"exact 1-11/16" | 1-11/16"exact 1-9/16" |
| 1-1/2" | 2"NEMA 1.984" | 2-1/16"exact 1-15/16" | 1-7/8"exact 1-3/4" |
| 2" | 2-1/2"NEMA 2.469" | 2-1/2"exact 2-3/8" | 2-3/8"exact 2-1/4" |
| 2-1/2" | 3"NEMA 2.969" | 3"exact 2-7/8" | n/a |
| 3" | 3-5/8"NEMA 3.594" | 3-5/8"exact 3-1/2" | n/a |
| 4" | 4-5/8"NEMA 4.641" | 4-5/8"exact 4-1/2" | n/a |
Easy clearance = smallest saw at least 1/8" over the pipe’s outside diameter (about 1/16" around it), the default. Exact fit = smallest saw at least the pipe’s outside diameter; “zero clearance” means the saw equals the pipe’s nominal outside diameter: it can bind, and pipe at the top of its tolerance won’t pass. Clear a coupling = the Sch 40 coupling hub plus 1/8". Into a box, conduit follows the NEMA knockout for the trade size, the same for EMT, PVC and rigid.
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Where these numbers come from
Outside diameters are copied from the makers’ and standards’ published tables. The hole saw sizes are not typed in: they’re worked out from those diameters and the sizes saw makers actually sell, then checked at build time so a recommended hole can never be smaller than what has to pass through it. Easy clearance is the smallest saw at least 1/8" bigger than the pipe; exact fit is the smallest saw at least the pipe’s size. Millimetres are converted from inches, not copied.
- Copper Development Association, Copper Tube Handbook, Tables 14.2a–c (ASTM B88)
- Zurn, PEX Plumbing Installation Guide (ZMKTG370-04)
- PPI / PPFA, PEX Design Guide, 2nd ed., ch. 9
- Viega, PureFlow Installation Manual
- Lenox, Hole Saws & Accessories catalog (sizes sold; pipe-entrance table)
- Starrett, Saws & Hand Tools catalogue (bi-metal sizes)
General sizing guidance from published pipe, conduit and hole saw dimensions. Before boring framing, check the hole limits in your local building code; for electrical work, follow your local electrical code and the fitting maker's instructions.