63/64 inch in mm and decimal

63/64 in = 0.984375 in = 25.003 mm. Closest metric drill: 20 mm.

Nearby drill sizes

Drill	Type	Inch	mm	Difference
59/64	fraction	.9219 in	23.416	-62.5 thou
15/16	fraction	.9375 in	23.812	-46.9 thou
61/64	fraction	.9531 in	24.209	-31.3 thou
31/32	fraction	.9688 in	24.606	-15.6 thou
63/64	fraction	.9844 in	25.003	0.0 thou
1 in	fraction	1.0000 in	25.400	15.6 thou

1 thou = 0.001 in = 0.0254 mm. Drills a few thou apart are usually interchangeable for clearance holes, but not for tap drills or reamer pilots.