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Drill Bit and Wall Anchor Size Chart
Matching bit size to fastener or anchor is what separates a snug hole from a stripped one or a loose one. As a rule for wood, pilot holes should be sized to the screw's root (inner) diameter, not its outer thread diameter, so threads still bite.
| Fastener/anchor | Recommended drill bit |
|---|---|
| #6 wood screw pilot (softwood) | 3/32 in (2.4 mm) |
| #8 wood screw pilot (softwood) | 1/8 in (3.2 mm) |
| #10 wood screw pilot (softwood) | 5/32 in (4 mm) |
| #8–10 wood screw pilot (hardwood) | 7/64–3/16 in, slightly larger than softwood |
| Plastic drywall anchor, standard | 3/16 in (4.8 mm) |
| Plastic drywall anchor, medium | 1/4 in (6.4 mm) |
| Self-drilling drywall anchor (plastic 'zip' type) | no pre-drill needed |
| Toggle bolt, 1/8 in | 1/2 in |
| Toggle bolt, 3/16 in | 1/2 in |
| Toggle bolt, 1/4 in | 5/8 in |
| Masonry anchor (plastic), 1/4 in screw | 3/16 in masonry bit |
| Masonry anchor (plastic), 3/8 in screw | 5/16 in masonry bit |
| Concrete screw (e.g., Tapcon), 3/16 in | 5/32 in masonry bit |
| Concrete screw (e.g., Tapcon), 1/4 in | 3/16 in masonry bit |
Notes
- Always check the specific anchor packaging — brands vary the required hole size by a hair even within the same nominal anchor size.
- For hollow-wall picture and shelf hanging above about 15–20 lb, a toggle bolt or metal self-drilling anchor holds meaningfully better than a plastic expansion anchor.
- Masonry bits need a hammer drill (or hammer function) to cut efficiently into concrete or brick; a standard bit alone will glaze and dull quickly.
Put this into practice
- Room Size and Furniture FitWill this furniture actually fit my room?
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