# 5/8" drill size

A 5/8 in drill is 0.6250 in (15.88 mm). It sits between 39/64 in and 41/64 in in the fractional series; the nearest metric drill is 15.9 mm.

## 5/8" drill data

- Series: Fractional drill
- Decimal: 0.6250 in
- Metric: 15.88 mm (15.8750 mm exact)
- Nearest metric drill: 15.9 mm (+0.025 mm)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 15.8 mm | 0.6220 | −0.075 mm |
| 15.9 mm | 0.6260 | +0.025 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| #1 | Number | 0.2280 | 5.79 |
| Letter Z | Letter | 0.4130 | 10.49 |
| 39/64" | Fractional | 0.6094 | 15.48 |
| 5/8" | Fractional | 0.6250 | 15.88 |
| 41/64" | Fractional | 0.6406 | 16.27 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| M18 × 2.5 | 15.5 mm | 65 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| M14 bolt | 14 mm | 1.88 mm | 0.94 mm | Normal fit (normal 15.5, loose 16.5 mm) |
| 9/16" bolt | 0.5625" | 0.0625" | 0.0312" | – |


## FAQ

**What size is a 5/8 in drill?**
A 5/8 in drill is 0.6250 in, which is 15.88 mm (15.8750 mm exactly).

**What is the metric equivalent of a 5/8 in drill?**
The nearest metric drill is 15.9 mm, 0.025 mm larger. The other close size is 15.8 mm.

**What thread can I tap with a 5/8 in drill?**
It leaves about 65 % thread in M18 × 2.5.

**What does a 5/8 in drill clear?**
It clears a 9/16" bolt with 0.0625" total clearance (0.0312" per side).

Source page: https://machinistcharts.com/drill-size/5-8-inch/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)