BenchReference / Drill sizes / 12.2 mm 12.2 mm Drill Decimal inches 0.4803″
Millimeters 12.2 mm
System Metric
Nearest equivalents in other systems System Nearest drill Size Difference Fractional inch 31/64″ 0.4844″ / 12.303 mm +0.103 mm (+0.0041″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −6.409 mm (−0.2523″)
Letter Z 0.4130″ / 10.49 mm −1.71 mm (−0.0673″)
−0.976 mm +0.976 mm 12.2 mm 12 mm −0.2 mm 12.1 mm −0.1 mm 12.3 mm +0.1 mm 12.4 mm +0.2 mm 31/64″ +0.103 mm ← #1 −6.409 mm ← Z −1.71 mm tick position = true diameter · metric neighbors above, equivalents below · window ±0.98 mm
Positive difference = cuts a slightly larger hole than 12.2 mm. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring metric sizes Drill Decimal in mm vs 12.2 mm 12 mm 0.4724 12 −0.2 mm 12.1 mm 0.4764 12.1 −0.1 mm 12.2 mm 0.4803 12.2 — 12.3 mm 0.4843 12.3 +0.1 mm 12.4 mm 0.4882 12.4 +0.2 mm
← 12.1 mm (smaller) 12.3 mm (larger) →
Compare 12.2 mm with another size
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 metric size is 12.2 mm. See all data sources .