# #13 drill size

A #13 drill is 0.1850 in (4.70 mm). It sits between #14 and #12 in the number series; the nearest metric drill is 4.7 mm.

## #13 drill data

- Series: Number drill
- Decimal: 0.1850 in
- Metric: 4.70 mm (4.6990 mm exact)
- Nearest metric drill: 4.7 mm (+0.001 mm)
- Nearest fractional: 3/16" (0.1875 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 4.6 mm | 0.1811 | −0.099 mm |
| 4.7 mm | 0.1850 | +0.001 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 11/64" | Fractional | 0.1719 | 4.37 |
| #14 | Number | 0.1820 | 4.62 |
| #13 | Number | 0.1850 | 4.70 |
| 3/16" | Fractional | 0.1875 | 4.76 |
| #12 | Number | 0.1890 | 4.80 |
| Letter A | Letter | 0.2340 | 5.94 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| #12-28 UNF | #14 | 67 |
| #12-24 UNC | #16 | 57 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| #5 screw | 0.1250" | 0.0600" | 0.0300" | – |
| #6 screw | 0.1380" | 0.0470" | 0.0235" | – |
| M4 bolt | 4 mm | 0.70 mm | 0.35 mm | Normal fit (normal 4.5, loose 4.8 mm) |
| #8 screw | 0.1640" | 0.0210" | 0.0105" | – |


## FAQ

**What size is a #13 drill?**
A #13 drill is 0.1850 in, which is 4.70 mm (4.6990 mm exactly).

**What is the metric equivalent of a #13 drill?**
The nearest metric drill is 4.7 mm, 0.001 mm larger. The other close size is 4.6 mm.

**What thread can I tap with a #13 drill?**
It leaves about 67 % thread in #12-28 UNF and 57 % in #12-24 UNC.

**Which fractional drill is closest to #13?**
3/16 in (0.1875 in) is the closest, 0.0025 in larger.

**What does a #13 drill clear?**
It clears a #8 screw with 0.0210" total clearance (0.0105" per side).

Source page: https://machinistcharts.com/drill-size/number-13/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)