BenchReference / Drill sizes / 5/8″ 5/8″ Drill Bit Decimal inches 0.6250″
Millimeters 15.875 mm
System Fractional inch
In 64ths 40/64″
Nearest equivalents in other systems System Nearest drill Size Difference Metric 16 mm 0.6299″ / 16 mm +0.125 mm (+0.0049″)
Number (wire gauge) #1 0.2280″ / 5.791 mm −10.084 mm (−0.3970″)
Letter Z 0.4130″ / 10.49 mm −5.385 mm (−0.2120″)
−1.27 mm +1.27 mm 5/8″ 19/32″ −0.794 mm 39/64″ −0.397 mm 41/64″ +0.397 mm 21/32″ +0.794 mm 16 mm +0.125 mm ← #1 −10.084 mm ← Z −5.385 mm tick position = true diameter · fractional neighbors above, equivalents below · window ±1.27 mm
Positive difference = cuts a slightly larger hole than 5/8″. Sizes
beyond the window are listed with arrows — they are not close substitutes.
Neighboring fractional sizes Drill Decimal in mm vs 5/8″ 19/32″ 0.5938 15.081 −0.794 mm 39/64″ 0.6094 15.478 −0.397 mm 5/8″ 0.6250 15.875 — 41/64″ 0.6406 16.272 +0.397 mm 21/32″ 0.6563 16.669 +0.794 mm
← 39/64″ (smaller) 41/64″ (larger) →
Compare 5/8″ 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 0.6250″. See all data sources .