BenchReference / Drill sizes / N N Drill Bit Decimal inches 0.3020″
Millimeters 7.671 mm
System Letter
Nearest equivalents in other systems System Nearest drill Size Difference Metric 7.7 mm 0.3031″ / 7.7 mm +0.029 mm (+0.0011″)
Fractional inch 19/64″ 0.2969″ / 7.541 mm −0.13 mm (−0.0051″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −1.88 mm (−0.0740″)
−0.614 mm +0.614 mm N L −0.305 mm M −0.178 mm O +0.356 mm P +0.533 mm 19/64″ −0.13 mm 7.7 mm +0.029 mm ← #1 −1.88 mm tick position = true diameter · letter neighbors above, equivalents below · window ±0.61 mm
Positive difference = cuts a slightly larger hole than N. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring letter sizes Drill Decimal in mm vs N L 0.2900 7.366 −0.305 mm M 0.2950 7.493 −0.178 mm N 0.3020 7.671 — O 0.3160 8.026 +0.356 mm P 0.3230 8.204 +0.533 mm
← M (smaller) O (larger) →
Compare N 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 letter size is 0.3020″. See all data sources .