# #44 drill size

A #44 drill is 0.0860 in (2.18 mm). It sits between #45 and #43 in the number series; the nearest metric drill is 2.2 mm.

## #44 drill data

- Series: Number drill
- Decimal: 0.0860 in
- Metric: 2.18 mm (2.1844 mm exact)
- Nearest metric drill: 2.2 mm (+0.016 mm)
- Nearest fractional: 3/32" (0.0938 in)

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 2.15 mm | 0.0846 | −0.034 mm |
| 2.2 mm | 0.0866 | +0.016 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 5/64" | Fractional | 0.0781 | 1.98 |
| #45 | Number | 0.0820 | 2.08 |
| #44 | Number | 0.0860 | 2.18 |
| #43 | Number | 0.0890 | 2.26 |
| 3/32" | Fractional | 0.0938 | 2.38 |
| Letter A | Letter | 0.2340 | 5.94 |

## Threads this drill can tap

| Thread | Standard drill | Thread % with this drill |
|---|---|---|
| #4-40 UNC | #43 | 80 |
| #3-56 UNF | #45 | 56 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| #1 screw | 0.0730" | 0.0130" | 0.0065" | – |
| M2 bolt | 2 mm | 0.18 mm | 0.09 mm | Tighter than close fit (2.2 mm) |


## FAQ

**What size is a #44 drill?**
A #44 drill is 0.0860 in, which is 2.18 mm (2.1844 mm exactly).

**What is the metric equivalent of a #44 drill?**
The nearest metric drill is 2.2 mm, 0.016 mm larger. The other close size is 2.15 mm.

**What thread can I tap with a #44 drill?**
It leaves about 80 % thread in #4-40 UNC and 56 % in #3-56 UNF.

**Which fractional drill is closest to #44?**
3/32 in (0.0938 in) is the closest, 0.0078 in larger.

**What does a #44 drill clear?**
It clears a M2 bolt with 0.18 mm total clearance (0.09 mm per side); for metric bolts: tighter than close fit.

Source page: https://machinistcharts.com/drill-size/number-44/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)