Drill bit size, minimum embedment, thread and wrench for wedge, sleeve, drop-in, nail drive, one-piece drive and pin anchors, concrete and heavy-duty screw anchors, lag shields, calk-ins and expansion shields — where two anchor makers agree. No load ratings: those come from the maker of the anchor.
Every concrete anchor is made for one drill bit size, and the hole matters as much as the anchor: too big and it won’t grip, too small and it won’t set. The bit isn’t always the anchor’s size — wedge and sleeve anchors take a bit the same diameter as the anchor, drop-ins and shields a larger one, concrete screws a smaller one. Pick the anchor for the base material and the job first (see Choosing the Right Anchor), then drill to this chart.
Loads come from the maker
No load figures on this chart. What an anchor holds depends on the anchor itself, the strength and condition of the concrete or masonry, how deep it is set, and how close it is to an edge or the next anchor — and each maker tests and publishes its own anchors, with different results. For tension, shear or pull-out values use the maker’s published data or ICC-ES evaluation report (ESR) for that exact anchor, and follow the engineer of record on anything structural, overhead or life-safety.
Torque, edge distance and spacing belong to the maker too — use the values in the maker’s instructions for your anchor.
| Type | How it holds | What it’s for | Drill bit |
|---|---|---|---|
| Wedge anchor | A threaded stud with a clip at the bottom; tightening the nut pulls the clip up into the hole wall | Permanent hold-downs in solid concrete: sill plates, racking, machinery | Same as the anchor |
| Sleeve anchor | A bolt inside a split sleeve; tightening the bolt draws a cone into the sleeve | Concrete, brick and block | Same as the sleeve |
| Drop-in anchor | An internally threaded shell set flush in the hole with a setting tool | A flush thread in concrete for a bolt or threaded rod that can be taken out later | Larger than the thread |
| Concrete screw | A hardened screw that cuts its own thread in a pre-drilled hole | Light to medium fastening in concrete, brick and block; removable | Smaller than the screw |
| Lag shield | A zinc alloy shell a lag screw expands as it is driven in | A lag screw in concrete, brick or block; short shield in hard material, long in soft | Larger than the lag screw |
| Calk-in anchor | A lead sleeve on a threaded cone, set by hammering the lead with a setting tool | A machine bolt in concrete, brick or block; light duty | Larger than the bolt |
| Single / double expansion shield | A zinc alloy shield that expands as a machine bolt is drawn into it | A machine bolt in concrete, brick or block | Larger than the bolt |
| Nail drive anchor | A zamac or nylon body with a nail; driving the nail flush spreads the body in the hole | Light-duty fastening to concrete, brick or block; not for overhead use | Same as the anchor |
| One-piece drive anchor | A one-piece steel anchor with a pre-formed end that grips the hole as it is driven | Fastening track, wood and forms to concrete | Same as the anchor |
| Pin-drive anchor | A threaded stud with a pin in its center; hammering the pin flush expands the end in the hole | Fastening to concrete with a nut and washer on the stud | Same as the anchor |
| Heavy-duty screw anchor | A hardened screw with a hex washer head that taps its own thread in the hole | Concrete and masonry; removable | Same as the screw |
| Anchor | Drill bit | Min. embedment | Stud thread | Nut wrench | Fixture hole |
|---|---|---|---|---|---|
| 1/4″ | 1/4″ | 1-1/8″ | 1/4″-20 | 7/16″ | 5/16″ |
| 3/8″ | 3/8″ | — | 3/8″-16 | 9/16″ | 7/16″ |
| 1/2″ | 1/2″ | 2-1/4″ | 1/2″-13 | 3/4″ | 9/16″ |
| 5/8″ | 5/8″ | 2-3/4″ | 5/8″-11 | 15/16″ | 11/16″ |
| 3/4″ | 3/4″ | — | 3/4″-10 | 1-1/8″ | — |
| 7/8″ | 7/8″ | — | 7/8″-9 | 1-5/16″ | — |
| 1″ | 1″ | 4-1/2″ | 1″-8 | 1-1/2″ | 1-1/8″ |
| 1-1/4″ | 1-1/4″ | — | 1-1/4″-7 | 1-7/8″ | 1-3/8″ |
| Sleeve | Drill bit | Bolt thread | Hex nut wrench |
|---|---|---|---|
| 1/4″ | 1/4″ | — | 3/8″ |
| 5/16″ | 5/16″ | 1/4″-20 | 7/16″ |
| 3/8″ | 3/8″ | 5/16″-18 | 1/2″ |
| 1/2″ | 1/2″ | 3/8″-16 | 9/16″ |
| 5/8″ | 5/8″ | 1/2″-13 | 3/4″ |
| 3/4″ | 3/4″ | 5/8″-11 | 15/16″ |
| Thread size | Drill bit | Min. embedment (flush) | Body length | Internal thread |
|---|---|---|---|---|
| 1/4″ | 3/8″ | 1″ | 1″ | 1/4″-20 |
| 3/8″ | 1/2″ | — | 1-9/16″ | 3/8″-16 |
| 1/2″ | 5/8″ | 2″ | 2″ | 1/2″-13 |
| 5/8″ | 7/8″ | 2-1/2″ | 2-1/2″ | 5/8″-11 |
| 3/4″ | 1″ | 3-3/16″ | — | 3/4″-10 |
| Screw | Drill bit | Min. embedment | Hex washer head | Phillips flat head |
|---|---|---|---|---|
| 3/16″ | 5/32″ | 1″ | 1/4″ | #2 |
| 1/4″ | 3/16″ | 1″ | 5/16″ | #3 |
| Lag screw | Shield | Drill bit | Min. embedment |
|---|---|---|---|
| 1/4″ | Short | 1/2″ | 1″ |
| 1/4″ | Long | 1/2″ | 1-1/2″ |
| 5/16″ | Short | 1/2″ | 1-1/4″ |
| 5/16″ | Long | 1/2″ | 1-3/4″ |
| 3/8″ | Short | 5/8″ | 1-3/4″ |
| 3/8″ | Long | 5/8″ | 2-1/2″ |
| 1/2″ | Short | 3/4″ | 2″ |
| 1/2″ | Long | 3/4″ | 3″ |
| 5/8″ | Short | 7/8″ | 2″ |
| 5/8″ | Long | 7/8″ | 3-1/2″ |
| 3/4″ | Short | 1″ | 2″ |
| Bolt size | Drill bit |
|---|---|
| #8 | 5/16″ |
| #10 | 3/8″ |
| 1/4″ | 1/2″ |
| 5/16″ | 5/8″ |
| 3/8″ | 3/4″ |
| 1/2″ | 7/8″ |
| Bolt size | Drill bit |
|---|---|
| 1/4″ | 1/2″ |
| 5/16″ | 5/8″ |
| 3/8″ | 3/4″ |
| 1/2″ | 7/8″ |
| 5/8″ | 1″ |
| 3/4″ | 1-1/4″ |
| Bolt size | Drill bit |
|---|---|
| 1/4″ | 1/2″ |
| 5/16″ | 5/8″ |
| 1/2″ | 7/8″ |
| 5/8″ | 1″ |
| Anchor | Drill bit |
|---|---|
| 3/16″ | 3/16″ |
| 1/4″ | 1/4″ |
| Anchor | Drill bit | Fixture hole |
|---|---|---|
| 3/16″ | 3/16″ | 1/4″ |
| 1/4″ | 1/4″ | 5/16″ |
| 3/8″ | 3/8″ | 7/16″ |
| Anchor | Drill bit |
|---|---|
| 3/8″ | 3/8″ |
| 1/2″ | 1/2″ |
| 5/8″ | 5/8″ |
| Screw anchor | Drill bit | Socket |
|---|---|---|
| 1/4″ | 1/4″ | — |
| 3/8″ | 3/8″ | 9/16″ |
| 1/2″ | 1/2″ | 3/4″ |
| 5/8″ | 5/8″ | 15/16″ |
| 3/4″ | 3/4″ | 1-1/8″ |
Drilling and setting
Drill with a carbide-tipped bit made to ANSI B212.15, in a hammer drill, the size on the chart for your anchor.
Clean the dust out of the hole before setting the anchor.
Wedge anchors: the bit is the anchor’s diameter; drill deeper than the anchor will be embedded. Wedge anchors are for solid concrete, not brick or block.
Sleeve anchors: the bit is the sleeve’s diameter. Sleeve anchors are used in concrete and in masonry.
Drop-in anchors are named by their internal thread and set with the setting tool made for that size. Drill the hole as deep as the anchor is long so it sits flush. Thread the bolt or rod in at least one diameter.
Concrete screws: use the bit size made for the screw, and drill at least 1/4″ deeper than the screw will be embedded.
Lag shields: drill the hole deeper than the shield is long. A short shield is for hard material, a long shield for softer material.
Nail drive anchors: the bit is the anchor’s diameter; drill at least 1/4″ deeper than the embedment so the nail can be driven flush. Not for overhead use.
One-piece drive anchors: the bit is the anchor’s diameter; drill deeper than the anchor will be embedded, then drive it through the part until the head is seated.
Pin-drive anchors: the bit is the anchor’s diameter; set the anchor through the part, then hammer the pin flush with the top of the anchor.
Heavy-duty screw anchors: the bit is the screw’s diameter. Use the bit your anchor’s maker specifies — some require their own matched-tolerance bit.
Calk-in anchors are set with their setting tool, hammering the lead sleeve down around the cone.
Quick answers
- What size drill bit for a 1/2 inch wedge anchor?
- A 1/2″ carbide bit — a wedge anchor takes a bit the same diameter as the anchor (two makers on our chart agree size by size).
- What size bit for a Tapcon or concrete screw?
- A 3/16″ concrete screw takes a 5/32″ bit and a 1/4″ screw takes a 3/16″ bit. The screw cuts its own thread, so the bit is smaller than the screw.
- What size hole for a 1/2 inch drop-in anchor?
- A 1/2″ drop-in (1/2″-13 internal thread) takes a 5/8″ bit, drilled 2″ deep to set it flush. Drop-ins are named by their thread, so the hole is bigger than the bolt.
- What size drill bit for a 3/8 lag shield?
- A 5/8″ bit, for both the short and the long 3/8″ lag shield.
- How much weight can a concrete anchor hold?
- There is no one number: it depends on the anchor, the concrete or masonry, the embedment, and the edge and spacing distances, and each maker publishes its own values. Use the maker’s published data or ICC-ES evaluation report for that exact anchor, and follow the engineer of record for structural work.
- What size wrench for a 1/2 inch wedge anchor?
- A 3/4″ wrench — the nut on a 1/2″-13 wedge anchor is a standard hex nut.