---
type: "drill"
designation: "23.5 mm"
series: "metric"
series_name: "Metric Drill Sizes"
diameter_in: 0.925197
diameter_mm: 23.5
standard: "ANSI/ASME B94.11M; BS 328"
verified: "August 1, 2026"
url: https://shopmath.org/drills/metric/23-5mm
---

# 23.5 mm Drill Bit Size — 0.9252 in / 23.500 mm

A 23.5 mm drill bit is 0.9252 in (23.500 mm) in diameter. It belongs to the metric series of standard twist drills.

- **Designation**: 23.5 mm
- **Series**: Metric
- **Diameter**: 0.9252 in (23.500 mm)

## 23.5 mm Drill Diameter

| Property | Value |
| --- | --- |
| Designation | 23.5 mm |
| Series | Metric |
| Diameter (in) | 0.9252 |
| Diameter (mm) | 23.500 |

## 23.5 mm Drill Equivalents in the Other Size Series

The nearest standard drill to 23.5 mm in each of the other three series. Nothing here is an exact match unless the difference column reads 0.0000 in.

| Series | Nearest drill | Diameter (in) | Diameter (mm) | Difference |
| --- | --- | --- | --- | --- |
| Number | [#1](https://shopmath.org/drills/number/1.md) | 0.2280 | 5.791 | -0.6972 in |
| Letter | [Z](https://shopmath.org/drills/letter/z.md) | 0.4130 | 10.490 | -0.5122 in |
| Fractional | [59/64](https://shopmath.org/drills/fractional/59-64.md) | 0.9219 | 23.416 | -0.0033 in |

## Sources and Method for the 23.5 mm Drill Size

### Drill index

- **Source**: Number/letter: bd_warehouse drill_sizes.csv (Apache-2.0) cross-checked against Wikipedia Drill bit sizes (CC BY-SA 4.0). Fractional: computed 1/64 in steps per ANSI B94.11M. Metric: computed BS 328 increment pattern.
- **Method**: computed
- **Verified against**: Wikipedia Drill bit sizes (CC BY-SA 4.0); 31/31 checks passed

### Assumptions

- Drill diameters are nominal. A worn or run-out drill cuts oversize; measure the hole, not the shank, when the fit matters.
- Dataset scope: Number sizes #61-#80 are stored but tagged demandTier 'extended' — query-space-map.md Appendix A found the tail thinning in the 60s. Sizes below #80 and metric sizes above 25.0 mm excluded.

**Data last verified**: August 1, 2026

## Common Questions About the 23.5 mm Drill Bit

### What size is a 23.5 mm drill bit size?

A 23.5 mm drill bit is 0.9252 in (23.500 mm) in diameter.

### What fraction is a 23.5 mm drill bit?

23.5 mm is 0.9252 in (23.500 mm), which is not itself a fractional size. The closest fractional drill is 59/64 at 0.9219 in (23.416 mm).

## Related pages

- Next size down (any series): [59/64](https://shopmath.org/drills/fractional/59-64.md) — 0.9219 in (23.416 mm)
- Next size up (any series): [23.75 mm](https://shopmath.org/drills/metric/23-75mm.md) — 0.9350 in (23.750 mm)
- Previous in the metric series: [23.25 mm](https://shopmath.org/drills/metric/23-25mm.md)
- Next in the metric series: [23.75 mm](https://shopmath.org/drills/metric/23-75mm.md)
- All metric sizes: [Metric drill sizes](https://shopmath.org/drills/metric.md)
- All drill sizes: [Drill bit size reference](https://shopmath.org/drills.md)
- Complete index by diameter: [Drill size chart](https://shopmath.org/charts/drill-sizes.md)
- Tap drills by thread: [Tap drill chart](https://shopmath.org/charts/tap-drill.md)

---

*Source: [ShopMath](https://shopmath.org/drills/metric/23-5mm) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*