Gauge Sizes

Body jewelry and needles tend to be identified by their gauge, using the Browne & Sharpe or American wire gauge system, at least in North America (many other regions simply use metric sizing). The larger the gauge, the smaller the diameter

Gauge	Decimal Inches	Fractional Inches		Millimeters
20ga	0.032	Approximately	1/32"	0.812mm
18ga	0.04	Larger than	1/32"	1.024mm
16ga	0.051	Smaller than	1/16"	1.291mm
14ga	0.064	Approximately	1/16"	1.628mm
12ga	0.081	Larger than	1/16"	2.053mm
10ga	0.102	Smaller than	1/8"	2.588mm
8ga	0.128	Approximately	1/8"	3.264mm
6ga	0.162	Larger than	1/8"	4.115mm
4ga	0.204	Smaller than	1/4"	5.189mm
2ga or 1/4"	0.258	Approximately	1/4"	6.544mm
0ga or 5/16"	0.325	Approximately	5/16"	8.251mm
00ga or 3/8"	0.365	Approximately	3/8"	9.266mm
000ga or 7/16"	0.410		7/16"	11.110mm
0000ga or 1/2"	0.460		1/2"	12.710mm
5/8"	0.630		5/8"	15.875mm
3/4"	0.750		3/4"	19.050mm

From 20 gauge to 00 gauge, the smaller the number is, the thicker the jewelry is. After 00, the diameter of body jewelry is usually measured in fractional inches as shown below

Body piercing demands a high level of sterilization when having the process done. The act should be completed with someone who has a lot of experience, as well as professional credentials. You don't want just anyone with a sharp needle to do work on your body. The piercing equipment should also be disposable, as well as sterilized. Many people turn to a friend for their first body piercing, but keep in mind that you run the serious risk of developing an infection. Also, be aware that if you do not keep your piercing holes open, they will close and the process will have to be done all over again.