1/8 inch in mm and decimal

1/8 in = 0.125 in = 3.175 mm. Closest metric drill: 3.2 mm.

Nearby drill sizes

Drill	Type	Inch	mm	Difference
#34	number	.1110 in	2.819	-14.0 thou
#33	number	.1130 in	2.870	-12.0 thou
#32	number	.1160 in	2.946	-9.0 thou
#31	number	.1200 in	3.048	-5.0 thou
1/8	fraction	.1250 in	3.175	0.0 thou
#30	number	.1285 in	3.264	3.5 thou
#29	number	.1360 in	3.454	11.0 thou
#28	number	.1405 in	3.569	15.5 thou
9/64	fraction	.1406 in	3.572	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.