BenchReference / Drill sizes / 57/64″ 57/64″ Drill Bit Decimal inches 0.8906″
Millimeters 22.622 mm
System Fractional inch
Nearest equivalents in other systems System Nearest drill Size Difference Metric 21 mm 0.8268″ / 21 mm −1.622 mm (−0.0639″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −16.831 mm (−0.6626″)
Letter Z 0.4130″ / 10.49 mm −12.132 mm (−0.4776″)
−1.81 mm +1.81 mm 57/64″ 55/64″ −0.794 mm 7/8″ −0.397 mm 29/32″ +0.397 mm 59/64″ +0.794 mm 21 mm −1.622 mm ← #1 −16.831 mm ← Z −12.132 mm tick position = true diameter · fractional neighbors above, equivalents below · window ±1.81 mm
Positive difference = cuts a slightly larger hole than 57/64″. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring fractional sizes Drill Decimal in mm vs 57/64″ 55/64″ 0.8594 21.828 −0.794 mm 7/8″ 0.8750 22.225 −0.397 mm 57/64″ 0.8906 22.622 — 29/32″ 0.9063 23.019 +0.397 mm 59/64″ 0.9219 23.416 +0.794 mm
← 7/8″ (smaller) 29/32″ (larger) →
Compare 57/64″ 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 fractional size is 0.8906″. See all data sources .