1/8 = .125 = 3.175 3/16 = .1875 = 4.7625 1/4 = .25 = 6.35 5/16 = .3125 = 7.9375 3/8 = .375 = 9.525 2.5 = 2.5 = 63.5

2.5 = 1/8 3-3.2 = 1/8 stock 4.7-5 = 3/16 5 = 1/4

Inches	Millimeters
0.0010	0.0254 mm
0.0015	0.0381 mm
0.0020	0.0508 mm
0.0025	0.0635 mm
0.0030	0.0762 mm
0.0035	0.0889 mm
0.0040	0.1016 mm
0.0045	0.1143 mm
0.0050	0.1270 mm
0.0055	0.1397 mm
0.0060	0.1524 mm
0.0065	0.1651 mm
0.0070	0.1778 mm
0.0075	0.1905 mm
0.0080	0.2032 mm
0.0085	0.2159 mm
0.0090	0.2286 mm
0.0100	0.2540 mm
0.0150	0.3810 mm
0.0200	0.5080 mm
0.0250	0.6350 mm
0.0300	0.7620 mm
0.0350	0.8890 mm
0.0400	1.0160 mm
0.0450	1.1430 mm
0.0500	1.2700 mm
0.0550	1.3970 mm
0.0600	1.5240 mm
0.0650	1.6510 mm
0.0700	1.7780 mm
0.0750	1.9050 mm
0.0800	2.0320 mm
0.0850	2.1590 mm
0.0900	2.2860 mm
0.1000	2.5400 mm
0.1500	3.8100 mm
0.2000	5.0800 mm
0.2500	6.3500 mm
0.3000	7.6200 mm
0.3500	8.8900 mm
0.4000	10.1600 mm
0.4500	11.4300 mm
0.5000	12.7000 mm
0.5500	13.9700 mm
0.6000	15.2400 mm
0.6500	16.5100 mm
0.7000	17.7800 mm
0.7500	19.0500 mm
0.8000	20.3200 mm
0.8500	21.5900 mm
0.9000	22.8600 mm