BenchReference

#4 Drill Bit

Decimal inches 0.2090″
Millimeters 5.309 mm
System Number (wire gauge)

Nearest equivalents in other systems

System Nearest drill Size Difference
Metric 5.3 mm 0.2087″ / 5.3 mm −0.009 mm (−0.0003″)
Fractional inch 13/64″ 0.2031″ / 5.159 mm −0.149 mm (−0.0059″)
Letter A 0.2340″ / 5.944 mm +0.635 mm (+0.0250″)
−0.425 mm+0.425 mm#4#6−0.127 mm#5−0.089 mm#3+0.102 mm#2+0.305 mm13/64″−0.149 mm5.3 mm−0.009 mmA +0.635 mm →tick position = true diameter · number neighbors above, equivalents below · window ±0.42 mm
Positive difference = cuts a slightly larger hole than #4. Sizes beyond the window are listed with arrows — they are not close substitutes.

Neighboring number sizes

Drill Decimal in mm vs #4
#6 0.2040 5.182 −0.127 mm
#5 0.2055 5.22 −0.089 mm
#4 0.2090 5.309 —
#3 0.2130 5.41 +0.102 mm
#2 0.2210 5.613 +0.305 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 0.2090″. See all data sources.