#15 drill size
A #15 drill is 0.1800 in (4.57 mm). It sits between #16 and #14 in the number series; the nearest metric drill is 4.6 mm.
#15 at a glance
Decimal, metric and the nearest sizes in the other series.
Nearest metric drills
Metric drills step by 0.05 mm below 3 mm and by 0.1 mm from 3 mm. Difference is metric minus inch size.
| Metric drill | Inch | Difference | In inches | Hole |
|---|---|---|---|---|
| 4.5 mm | 0.1772" | −0.072 mm | −0.0028" | Smaller |
| 4.6 mm | 0.1811" | +0.028 mm | +0.0011" | Larger |
Nearby inch drills
The next size down and up in each inch series, so you can pick a substitute from the drawer.
Threads a #15 drill can tap
Threads from the tap tables on this site that this drill can tap, with the thread percentage it leaves (55–85 % shown).
| Thread | Standard drill | Thread with this drill | Suits |
|---|---|---|---|
| #12-28 UNF | #14 | 78 % | Soft metals, plastics |
| #12-24 UNC | #16 | 67 % | Good in steel |
| M5 × 0.5 | 4.5 mm | 66 % | Good in steel |
Clearance for screws and bolts
Bolts and screws a #15 hole clears, with the diametral clearance and the gap each side. Metric sizes are compared with ISO 273.
| Fastener | Diameter | Clearance | Per side | ISO 273, metric only |
|---|---|---|---|---|
| #5 screw | 0.1250" | 0.0550" | 0.0275" | – |
| #6 screw | 0.1380" | 0.0420" | 0.0210" | – |
| M4 bolt | 4 mm | 0.57 mm | 0.29 mm | Normal fit (normal 4.5, loose 4.8 mm) |
| #8 screw | 0.1640" | 0.0160" | 0.0080" | – |
Inch clearance is the drill size minus the basic major diameter. A drilled hole usually cuts slightly oversize.
Number drill index
Every size in the series, holes drawn to scale.
Common questions
What size is a #15 drill?
A #15 drill is 0.1800 in, which is 4.57 mm (4.5720 mm exactly).
What is the metric equivalent of a #15 drill?
The nearest metric drill is 4.6 mm, 0.028 mm larger. The other close size is 4.5 mm.
What thread can I tap with a #15 drill?
It leaves about 78 % thread in #12-28 UNF and 67 % in #12-24 UNC.
Which fractional drill is closest to #15?
3/16 in (0.1875 in) is the closest, 0.0075 in larger.
What does a #15 drill clear?
It clears a #8 screw with 0.0160" total clearance (0.0080" per side).