What size drill bit for a wedge anchor?
Pick your wedge anchor size and get the drill bit — it's the same diameter as the anchor (1:1). A ½" wedge anchor takes a ½" bit.
Wedge anchor size
Common wedge anchor sizes — ¼" through ¾".
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How wedge anchor sizing works
Wedge anchors follow the 1:1 rule: the drill bit is the same diameter as the anchor. A ½" wedge anchor needs a ½" carbide bit, a ⅜" anchor a ⅜" bit — no undersizing like a Tapcon. The clip at the anchor’s tip flares against the wall of the hole as you torque the nut, so the hole has to be the anchor’s exact size: drill it oversize and the wedge can’t expand to grip (it pulls straight out); undersize and the anchor won’t seat.
Drill deeper than the anchor’s embedment so the tip has room, then blow or vacuum the dust out of the hole before setting — dust left in the hole is the most common reason a wedge anchor holds poorly.
Solid concrete only — not brick or block
This is the one thing to get right with a wedge anchor: it belongs in solid, poured concrete. The wedge grips by exerting a large, concentrated expansion force at its tip, and in brick, block, or hollow or brittle masonry that force splits the material and the anchor fails. Fastening to brick, block, or a mortar joint? Use a sleeve anchor instead — it spreads its force along the hole and is made for those walls. (For a concrete screw, see the Tapcon.) You also need the right tool: a hammer drill or rotary hammer with a carbide-tipped bit meeting ANSI B212.15 — a regular twist bit in a regular drill won’t cut concrete. For structural base plates, racking, seismic or edge-distance work, follow the anchor manufacturer’s engineered specs and consult a structural engineer.
Common questions
What size drill bit for a 3/8 wedge anchor?
A 3/8" wedge anchor uses a 3/8" carbide bit. Wedge anchors follow the 1:1 rule — the bit is the same diameter as the anchor — so a 1/2" anchor takes a 1/2" bit, a 5/8" anchor a 5/8" bit, and so on. Drill the hole to that exact size (oversize and the wedge can't grip), deeper than the anchor's embedment, and clear the dust before setting.
Can you use wedge anchors in brick?
No. A wedge anchor's expansion force is concentrated at the tip and will crack or split brick, block, and hollow or brittle masonry. Use it only in solid, poured concrete. For brick, block, or mortar joints, use a sleeve anchor, which spreads its force along the hole and is designed for those materials.
How deep do you drill for a wedge anchor?
Drill deeper than the anchor's embedment depth (the amount of anchor set into the concrete, per the manufacturer's chart for that diameter and load) so the tip has clearance, then vacuum or blow the dust out of the hole. A clean hole drilled slightly deeper than needed is what lets the anchor seat fully and hold; dust left in the hole is the most common cause of poor holding.
Do wedge anchors need a hammer drill?
Yes. Wedge anchors go into solid concrete, which needs the percussive action of a hammer drill or rotary hammer set to hammer-plus-rotation, with a carbide-tipped masonry bit (ANSI B212.15) matching the anchor diameter. A regular drill and twist bit won't cut a clean, correctly sized hole in concrete.
Full wedge anchor drill-bit chart
Download PDFWedge anchor drill bit size chart
| Wedge anchor size | Carbide drill bit |
|---|---|
| 1/4" | 1/4"6.4 mm |
| 3/8" | 3/8"9.5 mm |
| 1/2" | 1/2"12.7 mm |
| 5/8" | 5/8"15.9 mm |
| 3/4" | 3/4"19 mm |
The bit is the same diameter as the anchor — the 1:1 rule. The hole must match the anchor exactly: oversize and the wedge can’t expand to grip; undersize and it won’t seat. Drill deeper than the embedment and blow the hole clean.
Solid concrete only — wedge anchors split brick and block; use a sleeve anchor there. Requires a hammer drill and a carbide-tipped bit (ANSI B212.15).
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Where these numbers come from
The 1:1 bit-to-anchor rule is cross-referenced across major wedge-anchor manufacturers’ published instructions, which agree: the hole diameter equals the anchor diameter. Embedment depth, spacing and edge distance vary by diameter, load and concrete strength — always follow the specific anchor’s data sheet, and for structural or safety-critical work, an engineer. This page covers wedge anchors in solid concrete only; sleeve, Tapcon and drop-in anchors get their own pages.
Wedge anchors are for solid concrete only, and these are general DIY sizing conventions. For brick, block or mortar use a sleeve anchor. For structural, seismic, or code-governed work, follow the anchor manufacturer's engineered specifications and a structural engineer.