inches mm bolt conversion

Diameter/Decimal/Metric Chart for Small Diameters
Gauge or Diameter	Decimal (in)	mm
No. 0000	0.021	.53
No. 000	0.034	.86
No. 00	0.047	1.19
No. 0	0.060	1.524
No. 1	0.073	1.854
No. 2	0.086	2.184
No. 3	0.099	2.515
No. 4	0.112	2.845
No. 5	0.125	3.175
No. 6	0.138	3.505
No. 8	0.164	4.166
No. 10	0.190	4.826
No. 12	0.216	5.484
Fastener Conversion Chart
Inch Equivalent		Metric Size-Pitch ISO and IFI Rec.
UNC	UNF
1 - 64	1 - 72	M2 x 0.4
3 - 48	3 - 56	M2.5 x 0.45
4 - 40	4 - 48	M3 x .05
6 - 32	6 - 40	M3.5 x .06
8 - 32	8 - 36	M4 x .07
10 - 24	10 - 32	M5 x .08
1/4 - 20	1/4 - 28	M6 x 1
5/16 -18	5/16 - 24	M8 x 1.25
3/8 -16	3/8 - 24	M10 x 1.5
7/16 -14	7/16 - 20	M12 x 1.75
1/2 - 13	1/2 - 20	M14 x 2
5/8 - 11	5/8 - 18	M18 x 2
3/4 - 10	3/4 - 16	M20 x 2.5
1 - 8	1-12	M24 x 3
1-1/4 - 7	1-1/8 - 12	M30 x 3.5
1-1/2 - 6	1-1/4 - 12	M36 x 4