BenchReference

#22 Drill Bit

Decimal inches 0.1570″
Millimeters 3.988 mm
System Number (wire gauge)

Nearest equivalents in other systems

System Nearest drill Size Difference
Metric 4 mm 0.1575″ / 4 mm +0.012 mm (+0.0005″)
Fractional inch 5/32″ 0.1563″ / 3.969 mm −0.019 mm (−0.0008″)
Letter A 0.2340″ / 5.944 mm +1.956 mm (+0.0770″)
−0.319 mm+0.319 mm#22#24−0.127 mm#23−0.076 mm#21+0.051 mm#20+0.102 mm5/32″−0.019 mm4 mm+0.012 mmA +1.956 mm →tick position = true diameter · number neighbors above, equivalents below · window ±0.32 mm
Positive difference = cuts a slightly larger hole than #22. Sizes beyond the window are listed with arrows — they are not close substitutes.

Neighboring number sizes

Drill Decimal in mm vs #22
#24 0.1520 3.861 −0.127 mm
#23 0.1540 3.912 −0.076 mm
#22 0.1570 3.988 —
#21 0.1590 4.039 +0.051 mm
#20 0.1610 4.089 +0.102 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 0.1570″. See all data sources.