Concrete anchor drill bit size chart (wedge anchors, Tapcons, sleeve anchors)

Three anchor families, two drilling rules. Wedge anchors and inch-sized sleeve anchors take a drill bit equal to the anchor's nominal diameter. Tapcon screws take a bit one size smaller than the screw. And one exception that ruins holes: the Hilti HSL-3 metric sleeve anchor takes a bit equal to its outside diameter, not its thread size, so an M10 HSL-3 wants a 15 mm bit, not a 10 mm one. Every value below is copied from manufacturer installation tables, each row carries at least two independent manufacturer sources, and where manufacturers disagree on minimum embedment both numbers are printed rather than averaged away.

Concrete anchor drill bit sizes: the master chart

One table covers all three families. The inch column gives the bit diameter as a fraction with the decimal in parentheses where a cited source publishes it; the mm column gives the metric bit diameter; the embedment column gives the minimum embedment depth, attributed to the family whose table publishes it, because minimums differ between manufacturers at the same diameter. Rows for metric anchors leave the inch column as not published on purpose: no located manufacturer publishes inch bit sizes for metric wedge or HSL-3 sleeve anchors, and the ICC-ES report for fischer FAZ II anchors states use metric bits only. Blank cells are gaps in the published record, not conversions we skipped.

Row sources (footnotes; every row names at least two independent manufacturers except where flagged):

1. ITW Red Head, Trubolt Wedge Anchor Technical Data, Installation Information table (itwredhead.com).
2. Hilti, Anchor Fastening Technical Guide 2011, Kwik Bolt 3, Table 5 Specifications and Properties.
3. Simpson Strong-Tie, catalog C-A-2016, Strong-Bolt 2 Installation Data table.
4. Hilti, HST3 Technical Data Sheet ASSET-DOC-5412122, Setting details table.
5. fischer, international anchor catalogue, FAZ II technical data and loads tables.
6. Simpson Strong-Tie, catalog C-A-2023 p.119, Sleeve-All Anchor Installation Data, Drill Bit Size row.
7. ITW Red Head, Dynabolt Technical Data, Ultimate Tension and Shear Values in Concrete table, and catalog pp.84-85 anchor diameter and drill bit size columns.
8. Powers, Lok-Bolt spec sheet SPEC_47711825, Installation Specifications (ANSI drill bit size).
9. DeWALT, Power-Bolt+ Technical Guide, Anchor Installation Specifications.
10. Hilti, Anchor Fastening Technical Guide Ed.19 sec.3.3.2 Table 1, and HSL-3 ASD specification.
11. ICC Evaluation Service, ESR-1545 Tables 1 and 2. Flag: an independent evaluation report, not a manufacturer; no second manufacturer publishes HSL-3 bit sizes, so these rows rest on Hilti plus ICC-ES.
12. ITW Buildex, Tapcon Installation Instructions 1-7-21, Tapcon Anchor and Drill Bit Guide table (tapcon.com), and ITW Red Head Tapcon Screw Anchor Technical Data.
13. Simpson Strong-Tie, catalog C-A-2023 pp.126-133, Titen Turbo Installation Information and Additional Data, Drill Bit Diameter row.
14. Hilti, KWIK-CON+ document DBS 01/20 Table 3, and the Kwik Con+ KC 3/16 (4.8 mm) bit product page (hilti.com).

Supporting evaluation reports: ICC-ES ESR-2251 Table 2 and ESR-2302 Table 1 supply decimal-inch and mm bit figures where Simpson prints fractions only; ESR-2948 Tables 2 and 3 carry the fischer FAZ II bit diameters and the footnote use metric bits only. Decimal-inch sleeve values 0.250 through 0.750 are printed in the DeWALT Power-Bolt+ installation specifications, tied to the bit by that document's own statement that the nominal drill bit size is the same as the anchor diameter.

The chart as PDF and in mm

This page prints clean: the table has no clipped columns, needs no JavaScript, and carries a print stylesheet, so Print to PDF from any browser gives you the whole chart, sources included. For mm work, read the mm column directly; where it says not published for an inch-sized Tapcon bit, that is a gap in the published record (no manufacturer located publishes the 5/32 in Tapcon bit in mm), not an omission you should fill by converting, because a converted number is not a spec.

M8 concrete anchors

An M8 wedge anchor (Hilti HST3, fischer FAZ II) takes an 8 mm carbide bit, with minimum embedment 45 mm in the fischer table and 47 mm in the Hilti table. An M8 HSL-3 sleeve anchor is the trap: it takes a 12 mm bit because the bit matches the anchor's 12 mm outside diameter, with 60 mm minimum embedment. Section M8 wedge anchors below has the details.

M10 and 10 mm concrete anchors

M10 and 10 mm are the same diameter. An M10 wedge anchor takes a 10 mm bit, minimum embedment 40 mm (Hilti HST3) or 60 mm (fischer FAZ II). An M10 HSL-3 sleeve anchor takes a 15 mm bit with 70 mm minimum embedment. The common 10x50 mm wedge anchor is the M10 size with a 50 mm length, so it drills on the M10 row.

Wedge anchor drill bit sizes

The rule is short: the bit equals the nominal anchor diameter, at every size, inch or metric. That held across every wedge family in the source tables, Red Head Trubolt, Hilti Kwik Bolt 3 and HST3, Simpson Strong-Bolt 2, and fischer FAZ II. Two cautions travel with it. First, metric wedge anchors are drilled with metric bits only; no inch bit sizes are published for them. Second, the fischer FAZ II anchor body is slightly undersized (7.8, 9.8, 11.8, 15.7 mm outside diameter per ESR-2948 Table 3) while the required bit is the full 8, 10, 12, 16 mm, so never size the bit off a caliper measurement of the anchor.

Wedge anchor drill size charts

The master chart above is the wedge drill size chart: rows 1 through 4 (metric) and the five inch rows. Inch rows show fraction, decimal, and mm; metric rows show the mm bit only, per the published record.

M8 wedge anchors

8 mm bit. Minimum embedment 45 mm (fischer FAZ II) or 47 mm (Hilti HST3, the low end of its published 47 to 90 mm range). Use metric bits only.

M10 wedge anchors

10 mm bit. Minimum embedment 40 mm (Hilti HST3, low end of 40 to 59 mm) or 60 mm (fischer FAZ II). Covers the 10 mm and 10x50 mm anchor sizes.

M12 wedge anchors

12 mm bit. Minimum embedment 50 mm (Hilti HST3, low end of 50 to 69 mm) or 70 mm (fischer FAZ II).

M16 wedge anchors

16 mm bit. Minimum embedment 65 mm (Hilti HST3, low end of 65 to 84 mm) or 85 mm (fischer FAZ II).

3/8 in wedge anchors

3/8 in bit (0.375 in, 9.5 mm). Minimum embedment 1-1/2 in (Simpson Strong-Bolt 2), 1-5/8 in / 41 mm (Hilti Kwik Bolt 3), or 1-3/4 in / 44 mm (Red Head Trubolt). Red Head prints 1-3/4 in as its standard; the others publish their own minimums, all listed above.

1/2 in wedge anchors

1/2 in bit (0.5 in, 12.7 mm). Minimum embedment 1-7/8 in / 48 mm (Red Head Trubolt), 2-1/4 in / 57 mm (Hilti Kwik Bolt 3), or 2-1/4 in (Simpson Strong-Bolt 2).

Sleeve anchor drill bit sizes

Inch-sized sleeve anchors follow the same rule as wedge anchors: bit equals nominal diameter, verified in the Simpson Sleeve-All, Red Head Dynabolt, Powers Lok-Bolt, and DeWALT Power-Bolt+ tables, and stated in so many words by Simpson (drill bit diameter corresponds to nominal anchor diameter) and Red Head (use a bit whose diameter equals the anchor). The exception is metric: the Hilti HSL-3 takes a bit equal to its outside diameter, M8 to 12 mm, M10 to 15 mm, M12 to 18 mm, M16 to 24 mm, per ESR-1545 Table 2 where the OD values equal the listed bit diameters. Drilling a 10 mm hole for an HSL-3 M10 is the classic ruined-slab mistake.

Two sleeve diameters sometimes asked about, 5/16 in and M6, have no manufacturer-cited rows in the compiled research behind this page, so they are omitted rather than filled in by guesswork or conversion.

Tapcon screw size chart

Classic Tapcon screws cut their own threads, so the bit is smaller than the screw: 3/16 in screw takes a 5/32 in bit, 1/4 in screw takes a 3/16 in bit. Both pairings are published identically by ITW Buildex (Tapcon's maker) and Simpson Strong-Tie for its matching Titen Turbo, so the two rows in the master chart rest on two manufacturers agreeing verbatim. Hilti adds the metric figure for the large size: its matching Kwik Con+ bit is listed as 3/16 in, 4.8 mm.

Minimum embedment is where the makers split, and both numbers stand: ITW Buildex prints 1 in minimum for both classic diameters; Simpson prints 1 3/4 in nominal embedment for the Titen Turbo. Hilti's KWIK-CON+ tables list both 1 in and 1-3/4 in (25 and 44 mm) as valid nominal embedments. Read your box, then read your base material.

The Tapcon+ large-diameter line breaks the smaller-bit pattern by design: it uses same-size ANSI bits (1/4 takes 1/4, 3/8 takes 3/8, 1/2 takes 1/2, minimum embedment 2 in, 2-1/2 in, and 2 in respectively per the ITW installation table), and Simpson's Titen HD does the same. Tapcon+ 1/4 in anchors additionally require a tight-tolerance bit for Category 1 performance. Tapcon XL screws (5/16 in) use a 0.263 in pilot hole per the ITW technical data; that row rests on ITW documents only, with no second independent manufacturer located, so treat it as single-sourced.

Reading the table without getting burned

• Embedment varies by family at the same diameter. A 1/2 in sleeve anchor embeds 1-3/4 in (Simpson), 1-7/8 in (Red Head), 2-1/4 in (Powers), or 2-1/2 in (DeWALT). The chart prints all of them; your anchor's own spec sheet is the one that governs your hole.
• The BOLT DIA column trap. Red Head tables label the internal bolt thread as BOLT DIA (3/16 for a 1/4 in anchor, for example). That is the thread, not the drill size. The same convention appears in Simpson and Power-Bolt+ tables.
• Blanks are published gaps. No mm figure exists for the 5/32 in Tapcon bit from any manufacturer located (Milwaukee and Hilti Canada publish that bit inches-only), and no inch bit sizes exist for metric wedge anchors or the HSL-3. Filling those cells by converting inches to mm would manufacture a spec, so they stay blank.
• Drill the hole at least as deep as the embedment plus clearance. Every family's installation steps call for a hole deeper than the embedment so debris has somewhere to go; blow it out before setting the anchor.

The drill doing the work

Drilling these holes in concrete means hammer action and a carbide bit; a plain drill without hammer will spin forever and glaze the bit. Our picks by budget, including where the SDS-plus switch pays off, are in the best drills for concrete. The bit itself is covered in drill bits by material. And if this anchor is holding a ledger or a bracket to wood on the other side of the job, the wood-side hole is a different discipline entirely: that is the pilot hole chart, where the pilot is sized to the screw's root diameter, not its outside.

Quick answers

• What size bit for a 3/16 Tapcon? 5/32 in. ITW Buildex and Simpson agree verbatim.
• What size bit for a 1/4 Tapcon? 3/16 in, listed by Hilti as 4.8 mm. Tapcon+ 1/4 in is different: same-size 1/4 in ANSI bit.
• What size bit for a 3/8 wedge or sleeve anchor? 3/8 in (0.375 in, 9.5 mm). Bit equals nominal diameter for both families in inch sizes.
• What size bit for an M10 wedge anchor? 10 mm, metric bits only. An M10 HSL-3 sleeve anchor instead takes 15 mm.
• Does a 1/2 sleeve anchor drill bigger than a 1/2 wedge anchor? No. Both take a 1/2 in (12.7 mm) bit; they differ in minimum embedment, not hole size.
• Why do Tapcons use a smaller bit? They thread into concrete like a wood screw into wood. The undersized hole gives the threads something to cut.

Related guides

Also on this site: the best drills for concrete for the hammer drill that drills these holes, the masonry bit size chart for the full inch and mm size runs by shank type, the pilot hole chart for the wood side of the connection, drill bits by material for choosing masonry bits, and hammer drill vs regular drill for why hammer action matters here.