55/64 inch in mm and decimal

55/64 in = 0.859375 in = 21.828 mm. Closest metric drill: 20 mm.

Nearby drill sizes

Drill	Type	Inch	mm	Difference
51/64	fraction	.7969 in	20.241	-62.5 thou
13/16	fraction	.8125 in	20.637	-46.9 thou
53/64	fraction	.8281 in	21.034	-31.3 thou
27/32	fraction	.8438 in	21.431	-15.6 thou
55/64	fraction	.8594 in	21.828	0.0 thou
7/8	fraction	.8750 in	22.225	15.6 thou
57/64	fraction	.8906 in	22.622	31.3 thou
29/32	fraction	.9063 in	23.019	46.9 thou
59/64	fraction	.9219 in	23.416	62.5 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.