Quick answer: gauge describes the thickness of a piercing post or bar, while post length describes how long the straight section is from one end to the other. They are different measurements. In the common Brown & Sharpe gauge system used for body jewelry, 20G is about 0.8 mm, 18G about 1.0 mm and 16G about 1.2 mm. Always confirm the manufacturer's specification and have a professional piercer check the fit.
Gauge and post length are not the same
| Term | What it measures | Example |
|---|---|---|
| Gauge (G) | Post or bar thickness | 18G is approximately 1.0 mm |
| Post length | Length of the straight post | 6 mm or 8 mm, depending on the jewelry |
| Diameter | Width across a ring or hoop | Inner diameter is the opening |
| Thread type | How a removable end attaches | Internally threaded or threadless |
Common gauge conversions
The Association of Professional Piercers' conversion chart lists common sizes such as 20G at approximately 0.8 mm, 18G at 1.0 mm, 16G at 1.2 mm and 14G at 1.6 mm. Gauge numbers run in the opposite direction from thickness: a lower gauge number generally means a thicker post. See the APP gauge conversion chart for the full table.
Why post length must fit your anatomy
A post that is too short can press into the lobe, while one that is too long can move excessively and catch on hair or clothing. The correct length depends on the piercing location, tissue thickness, swelling stage and the jewelry's design. The APP's initial piercing jewelry guidance explains that jewelry must have an appropriate length or diameter and gauge for the individual anatomy and placement.
Important: ordinary fashion earrings are not automatically body-jewelry pieces suitable for fresh piercings. The APP specifically cautions that gold-filled and gold-plated jewelry are not appropriate for initial piercings. Do not use a fashion earring to replace initial jewelry without advice from a qualified piercer.
What to confirm before buying
- Ask whether the listing gives gauge, post length or hoop diameter.
- Check the unit: millimeters and gauge are not interchangeable.
- Confirm the closure and threading type.
- For a healing piercing, consult your piercer rather than estimating the size.
StaryMagic's The Fragment Triangle Minimalist Earring is a fashion earring with its own product details; do not assume it has a standard body-jewelry post specification. Browse the Geometric Earrings collection and check each listing for the dimensions provided.
Related guides
Read flat-back vs. butterfly-back earrings, screw-back vs. push-back closures, and how hoops should fit.
Frequently asked questions
Is 18G thicker than 20G?
Yes. In the common gauge system, a lower number indicates a thicker post.
Does gauge tell me how long the post is?
No. Gauge is thickness; post length is a separate measurement.
Is 20G the standard for every earring?
No. Fashion earrings and body jewelry use different designs and specifications. Check the product details.
Can I change the gauge of a fresh piercing myself?
Do not stretch or change a healing piercing on your own. Ask a qualified piercer to assess the jewelry and fit.
Shop with clear measurements: browse StaryMagic geometric earrings and review each product's listed dimensions before ordering.