Pilot hole calculator
Pick a screw gauge and whether you're driving into softwood or hardwood. This reads off the pilot and clearance drill sizes, so the screw grips instead of splitting the wood or spinning uselessly in an oversized hole.
Wood
Pilot hole
5/64"
Clearance hole
11/64"
In hardwood instead
3/32"
Every gauge, in softwood
- #2clearance 3/32"
- 1/32"
- #3clearance 7/64"
- 3/64"
- #4clearance 7/64"
- 3/64"
- #5clearance 1/8"
- 1/16"
- #6clearance 9/64"
- 1/16"
- #7clearance 5/32"
- 1/16"
- #8clearance 11/64"
- 5/64"
- #9clearance 3/16"
- 5/64"
- #10clearance 3/16"
- 3/32"
- #12clearance 7/32"
- 3/32"
- #14clearance 1/4"
- 7/64"
A widely reprinted shop reference, not a spec for one screw brand's thread form — treat it as a starting point for the drill index.
About pilot and clearance holes
- What size pilot hole do I need for a wood screw?
- It depends on the screw's gauge number and how hard the wood is — a #8 screw wants roughly a 5/64" pilot in softwood and 3/32" in hardwood. Pick the gauge stamped on the screw's box and this reads off both.
- Why does hardwood need a bigger pilot hole than softwood?
- A screw cuts its own threads into the pilot hole as it drives, displacing wood to either side. Softwood compresses out of the way; hardwood doesn't, so a hole sized for pine will split oak or snap the screw. Going slightly bigger in hardwood costs you nothing but drilling time.
- What's the difference between a pilot hole and a clearance hole?
- A pilot hole is sized so the screw's threads still bite; a clearance hole is sized so they don't, and the screw's shank passes through freely. Drill the clearance size in the piece you want to pull tight against the joint, and the pilot size in the piece the threads need to grip.
- Are these sizes exact for every screw brand?
- No — this is a widely reprinted shop reference, not a spec sheet for one manufacturer's thread form. Aggressive-thread deck screws and traditional wood screws behave differently even at the same gauge; treat this as a starting point for the drill index and adjust from experience with the screws you actually use.