The smallest gauge size for ears is typically 20 gauge or 18 gauge ^{1 2 3}. Standard ear piercings are usually done at 20g or 18g, which is roughly 1mm ². Gauge sizes go up (or down) in even numbers from there, so the next largest size from an 18g is 16g, then 14g, then 12g, and so on ⁴. When you get to 0g, the next size is 00g (pronounced “double zero gauge"), which is equal to about 3/8 of an inch ⁴.