What Drill Bit

Pilot hole size for a #10 screw

The #10 is a step up from the everyday #8 — a thicker, stronger screw for heavier holds: hinges, brackets, ledgers, thick hardwood and joints that take real load.

Because it's fatter, a #10 needs a slightly larger pilot hole than a #8. Skipping it in hardwood or near an edge is a common way to split the wood.

Change screw size

Covers #4–#14 wood screws — the common range.

Pilot hole sizes for a #10 screw

SoftwoodPine, fir, cedar, spruce
1/8in0.125" · 3.2 mm

Forgiving to drive — but pilot near the ends so it doesn't split.

HardwoodOak, maple, walnut, birch
9/64in0.141" · 3.6 mm

Splits easily — don't skip the pilot, and drive the screw slowly.

PlywoodPlywood, OSB, sheet goods
1/8in0.125" · 3.2 mm

Back it with scrap so it won't splinter on the exit side.

MDFMDF, particleboard
9/64in0.141" · 3.6 mm

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 #10 screw?

For a #10 screw, drill a 1/8" (3.2 mm) pilot hole in softwood, or 9/64" (3.6 mm) in hardwood. Plywood uses the softwood size; MDF uses the hardwood size.

What drill bit do I use for a #10 screw?

Use a 1/8" bit for softwood and a 9/64" 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 #10 screw?

Yes. Hardwood splits more easily, so a #10 screw takes a slightly larger 9/64" pilot hole versus 1/8" in softwood.

Do I need a pilot hole for a #10 screw in MDF?

Yes. MDF is dense and blows out near edges. Drill the hardwood size (9/64", 3.6 mm), go slowly, keep back from the edge, and use fine-thread screws.

Full pilot-hole chart

Straight-bit pilot sizes · fraction / mm · verified #4–#14
ScrewSoftwoodHardwood
#41/16"1.6 mm5/64"2.0 mm
#65/64"2.0 mm3/32"2.4 mm
#87/64"2.8 mm1/8"3.2 mm
#101/8"3.2 mm9/64"3.6 mm
#129/64"3.6 mm5/32"4.0 mm
#145/32"4.0 mm11/64"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.