What Drill Bit

Wood screw pilot hole chart (free printable PDF)

Straight-bit pilot-hole sizes for every common wood screw, #2 through #14. Fractions and millimetres, for softwood and hardwood — download the free printable PDF or print it straight from the page.

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Wood screw pilot hole chart

Pilot & clearance holes · fraction / mm · verified #2–#14
ScrewSoftwoodHardwoodClearance
#21/16"1.6 mm1/16"1.6 mm3/32"2.4 mm
#31/16"1.6 mm5/64"2.0 mm7/64"2.8 mm
#41/16"1.6 mm5/64"2.0 mm1/8"3.2 mm
#55/64"2.0 mm3/32"2.4 mm1/8"3.2 mm
#65/64"2.0 mm3/32"2.4 mm9/64"3.6 mm
#73/32"2.4 mm7/64"2.8 mm5/32"4.0 mm
#87/64"2.8 mm1/8"3.2 mm11/64"4.4 mm
#91/8"3.2 mm9/64"3.6 mm3/16"4.8 mm
#101/8"3.2 mm9/64"3.6 mm3/16"4.8 mm
#129/64"3.6 mm5/32"4.0 mm7/32"5.6 mm
#145/32"4.0 mm11/64"4.4 mm1/4"6.4 mm

Softwood / Hardwood = the pilot hole, drilled in the base piece  ·  Plywood uses Softwood, MDF uses Hardwood (fine-thread).
Clearance = the shank hole in the top board, so the screw slips through and pulls the joint tight. Sized a touch larger than the shank on purpose.

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How to read it

Each row is the pilot-hole drill bit for that screw gauge. Plywood follows the softwood column; MDF follows the hardwood column.

Have a decimal or millimetre size and need the physical bit? The drill bit size converter gives you the nearest actual drill bit for any size.

Split-safe — when in doubt, start one size smaller and test on scrap.

Where these numbers come from

Straight-bit pilot sizes for modern wood screws, sized to the screw’s root diameter so the hole grips without splitting. They’re 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 and fine-thread practice.

These are general guidance sizes cross-referenced from common woodworking sources. For structural, load-bearing, or manufacturer-specific work, follow the fastener manufacturer’s or an engineer’s specifications.