# #77 drill size

A #77 drill is 0.0180 in (0.46 mm). It sits between #78 and #76 in the number series; the nearest metric drill is 0.45 mm.

## #77 drill data

- Series: Number drill
- Decimal: 0.0180 in
- Metric: 0.46 mm (0.4572 mm exact)
- Nearest metric drill: 0.45 mm (−0.007 mm)
- Nearest fractional: 1/64" (0.0156 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 0.45 mm | 0.0177 | −0.007 mm |
| 0.5 mm | 0.0197 | +0.043 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 1/64" | Fractional | 0.0156 | 0.40 |
| #78 | Number | 0.0160 | 0.41 |
| #77 | Number | 0.0180 | 0.46 |
| #76 | Number | 0.0200 | 0.51 |
| 1/32" | Fractional | 0.0312 | 0.79 |
| Letter A | Letter | 0.2340 | 5.94 |


## FAQ

**What size is a #77 drill?**
A #77 drill is 0.0180 in, which is 0.46 mm (0.4572 mm exactly).

**What is the metric equivalent of a #77 drill?**
The nearest metric drill is 0.45 mm, 0.007 mm smaller. The other close size is 0.5 mm.

**Which fractional drill is closest to #77?**
1/64 in (0.0156 in) is the closest, 0.0024 in smaller.

Source page: https://machinistcharts.com/drill-size/number-77/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)