The most common type of question we get here at is about piercing jewelry size. We receive hundreds of emails daily and a majority of these email have to do with sizing and/or jewelry fitment. So let’s start with what are the units of body jewelry measurement.

Anyone who has tried to purchase body jewelry will know how confusing the measurements listed can be. Here is an example of the measurement information listed next to one of our plugs:

12 ga. – 3/8” (10 mm) with a wearable area of 6 mm.

That’s quite a lot to take in and if you’re unfamiliar with gauges, fractions and millimeter conversions, this string of information can seem like gibberish. So let’s break it down to manageable bite-sized pieces.

The first thing we’re presented with is 12 ga. What’s a gauge? And what does the 12 represent? The system used today to measure the gauge of the jewelry was actually created in the 1800’s for measuring electrical wires. The gauge of the wire represents its thickness. This way of measuring has been standardized, so 12 ga. jewelry from one manufacturer should be identical in size to another’s. One thing to note is that the higher the gauge number, the thinner the body jewelry. Typically, the smallest gauge available is 20, with 00 being the largest. Below is a handy conversion chart showing the corresponding gauge to millimeter conversion:



Once a piece of jewelry is made larger than the 00 measurement, then the size will be represented in inch-fraction sizes i.e. 1 ½” Check out the chart for larger pieces of body jewelry:


Moving on to the fraction/millimeter portion of the size. In our example, the plug we want to buy is 3/8” (10 mm).  These two measurement are actually representing the same thing; the diameter of the plug. The reason both the 3/8” and 10 mm are shown is so that American and international customers understand the size. Below is a handy millimeter to inch conversion cart:


The last thing listed is the 6 mm wearable area. Here, we’re being told that the area in which the lobe of the ear rests is 6 mm. Ear plugs are usually the only pieces of body jewelry that will have this listed.