---
type: "drill"
designation: "14.25 mm"
series: "metric"
series_name: "Metric Drill Sizes"
diameter_in: 0.561024
diameter_mm: 14.25
standard: "ANSI/ASME B94.11M; BS 328"
verified: "August 1, 2026"
url: https://shopmath.org/drills/metric/14-25mm
---

# 14.25 mm Drill Bit Size — 0.5610 in / 14.250 mm

A 14.25 mm drill bit is 0.5610 in (14.250 mm) in diameter. It belongs to the metric series of standard twist drills.

- **Designation**: 14.25 mm
- **Series**: Metric
- **Diameter**: 0.5610 in (14.250 mm)

## 14.25 mm Drill Diameter

| Property | Value |
| --- | --- |
| Designation | 14.25 mm |
| Series | Metric |
| Diameter (in) | 0.5610 |
| Diameter (mm) | 14.250 |

## 14.25 mm Drill Equivalents in the Other Size Series

The nearest standard drill to 14.25 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 | -0.3330 in |
| Letter | [Z](https://shopmath.org/drills/letter/z.md) | 0.4130 | 10.490 | -0.1480 in |
| Fractional | [9/16](https://shopmath.org/drills/fractional/9-16.md) | 0.5625 | 14.287 | +0.0015 in |

## Sources and Method for the 14.25 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 14.25 mm Drill Bit

### What size is a 14.25 mm drill bit size?

A 14.25 mm drill bit is 0.5610 in (14.250 mm) in diameter.

### What fraction is a 14.25 mm drill bit?

14.25 mm is 0.5610 in (14.250 mm), which is not itself a fractional size. The closest fractional drill is 9/16 at 0.5625 in (14.287 mm).

## Related pages

- Next size down (any series): [14 mm](https://shopmath.org/drills/metric/14mm.md) — 0.5512 in (14.000 mm)
- Next size up (any series): [9/16](https://shopmath.org/drills/fractional/9-16.md) — 0.5625 in (14.287 mm)
- Previous in the metric series: [14 mm](https://shopmath.org/drills/metric/14mm.md)
- Next in the metric series: [14.5 mm](https://shopmath.org/drills/metric/14-5mm.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/14-25mm) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*