Pilot hole size for a #4 screw
The #4 is one of the smallest common wood screws — for light, delicate work: trim and moulding, small hinges and catches, thin stock, craft and hobby builds, electronics and faceplate mounts, and little brackets.
A screw this small is easy to overpower, and thin or fragile material splits in a heartbeat near an edge — so the pilot hole matters most here. Here's the right bit for a #4 in every common material.
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Covers #4–#14 wood screws — the common range.
Pilot hole sizes for a #4 screw
Forgiving to drive — but pilot near the ends so it doesn't split.
Splits easily — don't skip the pilot, and drive the screw slowly.
Back it with scrap so it won't splinter on the exit side.
Dense — drill slowly and stay in from the edge, or it blows out.
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How to size a pilot hole
A pilot hole is a small guide hole you drill before the screw. Size it to the screw's root diameter — the solid core under the threads — and the threads still bite while the board isn't forced apart and split.
Split-safe — when in doubt, start one size smaller and test on scrap.
Common questions
What size hole should I predrill for a #4 screw?
For a #4 screw, drill a 1/16" (1.6 mm) pilot hole in softwood, or 5/64" (2.0 mm) in hardwood. Plywood uses the softwood size; MDF uses the hardwood size.
What drill bit do I use for a #4 screw?
Use a 1/16" bit for softwood and a 5/64" bit for hardwood. Those match the screw's root (inner) diameter, so the threads still grip but the wood isn't forced apart.
Is the pilot hole bigger in hardwood for a #4 screw?
Yes. Hardwood splits more easily, so a #4 screw takes a slightly larger 5/64" pilot hole versus 1/16" in softwood.
Do I need a pilot hole for a #4 screw in MDF?
Yes. MDF is dense and blows out near edges. Drill the hardwood size (5/64", 2.0 mm), go slowly, keep back from the edge, and use fine-thread screws.
Full pilot-hole chart
| Screw | Softwood | Hardwood |
|---|---|---|
| #4 | 1/16"1.6 mm | 5/64"2.0 mm |
| #6 | 5/64"2.0 mm | 3/32"2.4 mm |
| #8 | 7/64"2.8 mm | 1/8"3.2 mm |
| #10 | 1/8"3.2 mm | 9/64"3.6 mm |
| #12 | 9/64"3.6 mm | 5/32"4.0 mm |
| #14 | 5/32"4.0 mm | 11/64"4.4 mm |
Softwood — pine, fir, cedar, spruce · Plywood uses the Softwood column.
Hardwood — oak, maple, walnut, birch · MDF uses the Hardwood column (use fine-thread screws).
Where these numbers come from
Straight-bit pilot sizes for modern wood screws, sized to the screw’s root diameter — a standard woodworking approach for a hole that grips without splitting — and cross-referenced against widely used charts (Bolt Depot, McFeely’s, WorkshopCalc). We lean slightly larger than the strength-optimized minimums, because for most projects not splitting the board matters more than maximum holding power. Plywood follows softwood; MDF follows hardwood / fine-thread practice.