Body jewelry can be measured in both inches and millimeters. The charts below show the various gauges and lengths in both inches and millimeters.

Gauge	Inches	Millimeters
0000	.460	11.684
000	.410	10.404
00	.365	9.266
0	.325	8.26
2	.257	6.54
4	.204	5.19
6	.162	4.12
8	.128	3.26
10	.102	2.59
12	.081	2.05
14	.064	1.63
16	.051	1.29
18	.040	1.02
20	.032	.812

Inches	Decimal inches	Millimeters
1/8" (shortest)	.125	3.2
3/16"	.1875	4.8
1/4"	.250	6.4
5/16"	.3125	7.94
3/8"	.375	9.5
7/16"	.4375	11.11
1/2"	.500	12.7
9/16"	.5625	14.29
5/8"	.625	15.9
11/16"	.6875	17.46
3/4"	.750	19.0
13/16"	.8125	20.64
7/8"	.875	22.2
15/16"	.9375	23.81
1"	1.000	25.4
1-1/4"	1.25	31.75
1-5/16"	1.3125	33.34
1-3/8"	1.375	34.93
1-7/16"	1.4375	36.51
1-1/2"	1.5	38.1
1-9/16"	1.5625	39.69
1-5/8"	1.625	41.28
1-11/16"	1.6875	42.86
1-3/4"	1.75	44.45
1-13/16"	1.8125	46.04
1-7/8"	1.875	47.63
1-15/16"	1.9375	49.21
2" (longest)	2	50.8