BenchReference / Drill sizes / 3.5 mm 3.5 mm Drill Decimal inches 0.1378″
Millimeters 3.5 mm
System Metric
Nearest equivalents in other systems System Nearest drill Size Difference Fractional inch 9/64″ 0.1406″ / 3.572 mm +0.072 mm (+0.0028″)
Number (wire gauge) #29 0.1360″ / 3.454 mm −0.046 mm (−0.0018″)
Letter A 0.2340″ / 5.944 mm +2.444 mm (+0.0962″)
−0.28 mm +0.28 mm 3.5 mm 3.3 mm −0.2 mm 3.4 mm −0.1 mm 3.6 mm +0.1 mm 3.7 mm +0.2 mm #29 −0.046 mm 9/64″ +0.072 mm A +2.444 mm → tick position = true diameter · metric neighbors above, equivalents below · window ±0.28 mm
Positive difference = cuts a slightly larger hole than 3.5 mm. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring metric sizes Drill Decimal in mm vs 3.5 mm 3.3 mm 0.1299 3.3 −0.2 mm 3.4 mm 0.1339 3.4 −0.1 mm 3.5 mm 0.1378 3.5 — 3.6 mm 0.1417 3.6 +0.1 mm 3.7 mm 0.1457 3.7 +0.2 mm
← 3.4 mm (smaller) 3.6 mm (larger) →
Compare 3.5 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 3.5 mm. See all data sources .