What Drill Bit

Lag screws

Everything for lag screw pilot holes — the finder by diameter and wood type, and the full chart, ¼" to ¾".

Start here Lag screw pilot-hole finder Pick lag-bolt diameter and wood type and get the pilot-hole size, plus the shank clearance hole. Open the finder Reference Lag screw pilot hole chartPilot sizes by lag diameter and wood type, plus the shank clearance hole.

By bolt diameter

Know your lag size? Go right to it.

1/4"lagSoft 3/32" · Hard 3/16" 3/8"lagSoft 11/64" · Hard 1/4" 1/2"lagSoft 15/64" · Hard 11/32" 5/16"lagSoft 9/64" · Hard 13/64" 5/8"lagSoft 5/16" · Hard 29/64" 3/4"lagSoft 13/32" · Hard 9/16"

Other fasteners

Wood screwsPocket screwsDrill bit sizes sizing & conversionGuides

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.