Drill Bit Size Chart
What size drill bit do you need?It depends on two things: what you are drilling into, and what is going into the hole. A 3/8″ wedge anchor needs a 3/8″ bit. A #8 wood screw needs a 7/64″ pilot in softwood. Porcelain tile needs diamond, not carbide, at any size.
The selector below asks a few questions and gives you the bit type, the size and the technique for your exact job. If you would rather read the numbers straight off a chart, they are all further down — drill bit sizes by anchor, by screw gauge, by material, and the RPM for each.
Concrete Anchor Drill Bit Size Chart
The drill bit must match the anchor exactly. The most common sizes are below — for every diameter of every anchor type, see the full drill bit size chart for concrete anchors.
| Anchor Type | Anchor Size | Drill Bit Size | Bit Type | Min Embedment |
|---|---|---|---|---|
| Tapcon Screw | 3/16" | 5/32" | Carbide Masonry | 1" |
| Tapcon Screw | 1/4" | 3/16" | Carbide Masonry | 1-1/4" |
| Wedge Anchor | 3/8" | 3/8" | Carbide Masonry | 2-1/4" |
| Wedge Anchor | 1/2" | 1/2" | Carbide Masonry | 3-1/2" |
| Sleeve Anchor | 3/8" | 3/8" | Carbide Masonry | 2-1/4" |
| Drop-In Anchor | 3/8" | 1/2" | Carbide Masonry | 1-5/8" |
Screw Pilot Hole Size Chart
A pilot hole sits just under the screw's root diameter so the threads bite without splitting the wood. Hardwood needs a larger pilot than softwood for the same screw. Full breakdown, including metric, lag and sheet metal screws, in the pilot hole guide.
| Screw Gauge | Shank Dia. | Softwood Pilot | Hardwood Pilot | Clearance Hole |
|---|---|---|---|---|
| #4 | 0.112" | 3/64" | 1/16" | 1/8" |
| #6 | 0.138" | 5/64" | 3/32" | 9/64" |
| #8 | 0.164" | 7/64" | 1/8" | 11/64" |
| #9 | 0.177" | 7/64" | 9/64" | 3/16" |
| #10 | 0.190" | 9/64" | 9/64" | 3/16" |
| #12 | 0.216" | 5/32" | 11/64" | 7/32" |
| #14 | 0.242" | 11/64" | 3/16" | 1/4" |
Drill Bit Types by Material
Using the wrong bit type damages the bit and the material. Match your bit to the material every time — the drill bit material guide explains what HSS, cobalt and carbide actually mean.
| Material | Best Bit Type | Bit Material | Drill Mode | Use Cutting Oil? |
|---|---|---|---|---|
| Concrete | Carbide Masonry | Carbide Tip | Hammer Mode | No |
| Brick | Carbide Masonry | Carbide Tip | Hammer Mode | No |
| Block (CMU) | Carbide Masonry | Carbide Tip | Hammer Mode | No |
| Mild Steel | Twist Bit | Cobalt or HSS | Regular | Yes |
| Stainless Steel | Twist Bit | Cobalt M42 | Regular (slow) | Yes |
| Hardwood | Brad-Point | HSS | Regular | No |
| Softwood | Brad-Point or Spade | HSS | Regular | No |
| Ceramic Tile | Diamond-Tipped | Diamond | Regular (no hammer) | Water |
| Porcelain Tile | Diamond Core | Diamond | Regular (no hammer) | Water |
| Glass | Diamond-Tipped Spear | Diamond | Regular (slow) | Water |
| Aluminum | Twist Bit | HSS or Cobalt | Regular | Yes |
| Cast Iron | Twist Bit | HSS | Regular (slow) | No (dry) |
Drill Bit Speed Guide (RPM by Material)
Too fast burns the bit. Too slow wastes time. These ranges are starting points; the full speed guide covers why large-diameter bits run slower than small ones.
| Material | 1/8" bit | 1/4" bit | 3/8" bit | 1/2" bit |
|---|---|---|---|---|
| Softwood | 3,000 | 2,000 | 1,500 | 1,000 |
| Hardwood | 2,500 | 1,500 | 1,000 | 750 |
| Mild Steel | 3,000 | 1,500 | 1,000 | 750 |
| Stainless Steel | 1,500 | 750 | 500 | 350 |
| Aluminum | 4,000 | 2,500 | 2,000 | 1,500 |
| Concrete | Use hammer mode - RPM less important | |||
| Tile/Glass | 600 | 400 | 300 | 200 |
RPM values are approximate starting points. Adjust based on bit size, material hardness, and heat buildup.