Drill Bit Size Calculator — Screw Pilot Holes
Find the correct drill bit size for screws, dowels, and pilot holes in wood.
The gauge number stamped on the screw box
Denser woods need larger pilot holes
Determines whether countersinking is needed
How We Calculate This
Pilot hole sizes depend on screw gauge and wood type. Hardwood needs larger pilot holes than softwood because it is denser and more likely to split.
- Pilot hole: Slightly smaller than the screw root diameter
- Clearance hole: Matches the screw shank diameter
- Countersink: Matches the screw head diameter
- Pilot depth: Screw length minus top piece thickness
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.