# #43 drill size

A #43 drill is 0.0890 in (2.26 mm). It is the standard tap drill for #4-40 UNC; the nearest metric drill is 2.25 mm.

## #43 drill data

- Series: Number drill
- Decimal: 0.0890 in
- Metric: 2.26 mm (2.2606 mm exact)
- Nearest metric drill: 2.25 mm (−0.011 mm)
- Nearest fractional: 3/32" (0.0938 in)
- Standard tap drill for: #4-40 UNC

## Nearest metric drills

| Metric drill | Inch | Difference |
|---|---|---|
| 2.25 mm | 0.0886 | −0.011 mm |
| 2.3 mm | 0.0906 | +0.039 mm |

## Nearby inch drills

| Drill | Series | Inch | mm |
|---|---|---|---|
| 5/64" | Fractional | 0.0781 | 1.98 |
| #44 | Number | 0.0860 | 2.18 |
| #43 | Number | 0.0890 | 2.26 |
| #42 | Number | 0.0935 | 2.37 |
| 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 | 71 |
| #4-48 UNF | #42 | 85 |

## Clearance

| Fastener | Diameter | Clearance | Per side | ISO 273 |
|---|---|---|---|---|
| #1 screw | 0.0730" | 0.0160" | 0.0080" | – |
| M2 bolt | 2 mm | 0.26 mm | 0.13 mm | Close fit (close 2.2, normal 2.4 mm) |
| #2 screw | 0.0860" | 0.0030" | 0.0015" | – |


## FAQ

**What size is a #43 drill?**
A #43 drill is 0.0890 in, which is 2.26 mm (2.2606 mm exactly).

**What is the metric equivalent of a #43 drill?**
The nearest metric drill is 2.25 mm, 0.011 mm smaller. The other close size is 2.3 mm.

**What tap uses a #43 drill?**
A #43 drill is the standard tap drill for #4-40 UNC (about 71 % thread).

**Which fractional drill is closest to #43?**
3/32 in (0.0938 in) is the closest, 0.0048 in larger.

**What does a #43 drill clear?**
It clears a #2 screw with 0.0030" total clearance (0.0015" per side).

Source page: https://machinistcharts.com/drill-size/number-43/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)