Gauges on an earring chart refer to the thickness of the earring post or wire that goes through your ear piercing. Here are some key points about earring gauges:

1. Standard ear piercings are usually pierced at 20g or 18g (approx. 1mm).
2. Gauge sizes go up in even numbers from there (16g, 14g, 12g, 10g, etc.).
3. After 00g (which is 9.2mm), sizes are referred to in millimeters (mm) or fractions of an inch ^{1 2}.