What size is a 15/64" drill bit?

A 15/64" drill bit is 0.2344 in in diameter, which is 5.953 mm. It is the 15/64 in fractional size.

What is the metric equivalent of a 15/64" drill bit?

The closest metric drill to a 15/64" drill bit (5.953 mm) is 6 mm, which is 6.000 mm — 0.0018 in larger.

What bolt fits through a 15/64" drill bit hole?

A hole drilled with a 15/64" drill bit is the standard loose clearance hole for #10-32 UNF, and a clearance hole for 1 other fastener sizes listed on this page.

Fractional drill · 15/64

15/64" Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes

https://shopmath.org/drills/fractional/15-64 · data verified August 1, 2026

A 15/64" drill bit is 0.2344 in (5.953 mm) in diameter. Diameters are nominal.

Series: Fractional
Designation: 15/64
Inch: 0.2344
mm: 5.953
Standard: ANSI/ASME B94.11M

Fractional Drill · 15/64 · nominal diameter

0.2344 in

Millimetre: 5.953mm
Fraction: 15/64in

Nominal diameter. A worn or run-out drill cuts oversize, which leaves less thread in a tapped hole than the table says.

15/64" Drill Bit Size in Inches and Millimetres

The nominal diameter of a 15/64" drill bit. Drill sizes are nominal — a worn drill, run-out or a soft material that closes in behind the cut all move the finished hole.

15/64" drill bit — decimal inch and millimetre diameter
Property	Value
Diameter, decimal inch	0.2344 in
Diameter, millimetre	5.953 mm
Fraction	15/64 in
Cross-sectional area	0.04314 in²

1 in = 25.4 mm exactly, so the two columns are the same value in different units, not two measurements.

Fasteners That Pass Through a 15/64" Drill Bit Hole

A hole drilled with a 15/64" drill bit is the standard clearance hole for these fasteners — the through-hole the bolt passes freely, not the tapped hole.

Fasteners whose clearance hole is drilled with a 15/64" drill bit
Fastener	Series	Clearance class
#10-32 UNF	Unified Fine (UNF)	loose
#10-24 UNC	Unified Coarse (UNC)	loose

Clearance classes per ISO 273 (metric) and ASME B18.2.8 (inch): close for located joints, normal for general assembly, loose for slotted or adjustable joints.

15/64" Drill Bit Equivalents in Every Other Drill Series

The closest size to the 15/64" drill bit in each of the other three indexes, with the difference in inches. None of them is the same drill — check the difference before substituting one into a tapped hole.

Nearest number, letter, fractional and metric equivalents to a 15/64" drill bit
Property	Property	Diameter		Property
Drill	Series	in	mm	Difference, in
#1	Number	0.2280	5.791	−0.0064
A	Letter	0.2340	5.944	−0.0004
6 mm	Metric	0.2362	6.000	+0.0018

A positive difference means the equivalent drill is larger, which leaves less thread in a tapped hole. Sizes without a link are stored for the nearest-drill calculation but do not carry their own page.

Drill Sizes Either Side of the 15/64" Drill Bit

Ordered by diameter across all four indexes, so the next size up may be a letter, a fraction or a metric drill rather than the next one in this series.

Standard drill sizes adjacent to a 15/64" drill bit, by diameter
Property	Property	Diameter
Drill	Series	in	mm
5.9 mm	Metric	0.2323	5.900
A	Letter	0.2340	5.944
15/64"	Fractional	0.2344	5.953
6 mm	Metric	0.2362	6.000
B	Letter	0.2380	6.045

Sources and Method for the 15/64" Drill Bit Size

Drill diametercomputed

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.

Verified against Wikipedia Drill bit sizes (CC BY-SA 4.0); 31/31 checks passed

Computed from the standard's formulas, then checked against published tables.

Formula

Fractional drill diameter

Ø  =  15/64 in  =  0.2344 in

Fractional drills are exact fractions of an inch in 1/64 in steps; the decimal is the fraction evaluated, not a measurement.

Assumptions

Diameters are nominal. Drill manufacturing tolerance, wear and run-out all cut oversize, and every one of those moves a tapped hole toward less thread than the table says.
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

How this data is built and checked →

How to Cite This 15/64" Drill Bit Reference

Citation

ShopMath. "15/64" Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes." ShopMath, verified August 1, 2026, https://shopmath.org/drills/fractional/15-64

BibTeX

@misc{shopmath-drills-fractional-15-64,
  title        = {15/64" Drill Bit Size — Decimal Inch, Millimetre and Tap Sizes},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/drills/fractional/15-64}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/drills/fractional/15-64

Common Questions About the 15/64" Drill Bit

What size is a 15/64" drill bit?: A 15/64" drill bit is 0.2344 in in diameter, which is 5.953 mm. It is the 15/64 in fractional size.
What is the metric equivalent of a 15/64" drill bit?: The closest metric drill to a 15/64" drill bit (5.953 mm) is 6 mm, which is 6.000 mm — 0.0018 in larger.
What bolt fits through a 15/64" drill bit hole?: A hole drilled with a 15/64" drill bit is the standard loose clearance hole for #10-32 UNF, and a clearance hole for 1 other fastener sizes listed on this page.

All fractional drill sizes · Complete drill size chart · Every drill series