# #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 drill data

- Series: Number drill
- Decimal: 0.1800 in
- Metric: 4.57 mm (4.5720 mm exact)
- Nearest metric drill: 4.6 mm (+0.028 mm)
- Nearest fractional: 3/16" (0.1875 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 4.5 mm | 0.1772 | −0.072 mm |
| 4.6 mm | 0.1811 | +0.028 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 11/64" | Fractional | 0.1719 | 4.37 |
| #16 | Number | 0.1770 | 4.50 |
| #15 | Number | 0.1800 | 4.57 |
| #14 | Number | 0.1820 | 4.62 |
| 3/16" | Fractional | 0.1875 | 4.76 |
| Letter A | Letter | 0.2340 | 5.94 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| #12-28 UNF | #14 | 78 |
| #12-24 UNC | #16 | 67 |
| M5 × 0.5 | 4.5 mm | 66 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| #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" | – |


## FAQ

**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).

Source page: https://machinistcharts.com/drill-size/number-15/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)