#27 Drill Bit

Decimal inches 0.1440″

Millimeters 3.658 mm

System Number (wire gauge)

Nearest equivalents in other systems

System	Nearest drill	Size	Difference
Metric	3.7 mm	0.1457″ / 3.7 mm	+0.042 mm (+0.0017″)
Fractional inch	9/64″	0.1406″ / 3.572 mm	−0.086 mm (−0.0034″)
Letter	A	0.2340″ / 5.944 mm	+2.286 mm (+0.0900″)

Positive difference = cuts a slightly larger hole than #27. Sizes beyond the window are listed with arrows — they are not close substitutes.

Clearance drill for

Thread	Fit
#4-40 UNC	loose
#4-48 UNF	loose

Neighboring number sizes

Drill	Decimal in	mm	vs #27
#29	0.1360	3.454	−0.203 mm
#28	0.1405	3.569	−0.089 mm
#27	0.1440	3.658	—
#26	0.1470	3.734	+0.076 mm
#25	0.1495	3.797	+0.14 mm

Data provenance. ASME B94.11M, Twist Drills (standard drill size series) (ASME). Millimeter and inch values are converted with the exact definition 1 in = 25.4 mm; the canonical dimension for this number size is 0.1440″. See all data sources.