Piercing Gauge to MM Conversion Chart: Stop Guessing, Start Shopping
Ask five different piercers what a 16G means in millimeters and you might get five slightly different answers. Gauge sizing is one of the most confusing parts of buying body jewelry — the numbers run backwards, the abbreviations look like a foreign language, and one wrong guess means jewelry that either won't fit or won't stay in. We're fixing that right now.
Whether you're shopping for your first stud or building out a full stretched-ear collection, here's the no-fluff breakdown of gauge sizing so you never have to second-guess a cart checkout again.
What Does "Gauge" Actually Mean?
Gauge (G) measures the thickness of the jewelry's post or wire — not the size of the piercing hole, not the length of the barbell, just the diameter of the metal itself. The system comes from an old wire-measuring standard, which is why it runs opposite to what you'd expect.
The lower the gauge number, the thicker the jewelry. An 18G stud is thinner than a 16G stud, which is thinner than a 14G stud. Once you're past 00G, sizing switches to straight fractional inches, since the gauge scale doesn't go any lower.
The Full Gauge to MM Conversion Chart
| Gauge | Millimeters | Common Use |
|---|---|---|
| 20G | 0.8mm | Delicate nose studs, some cartilage |
| 18G | 1.0mm | Standard nose piercings, lobes |
| 16G | 1.2mm | Cartilage, helix, tragus, septum |
| 14G | 1.6mm | Standard lobes, navel, nipple, initial piercings |
| 12G | 2.0mm | Stretched lobes (early stage) |
| 10G | 2.4mm | Stretched lobes |
| 8G | 3.2mm | Stretched lobes |
| 6G | 4.0mm | Stretched lobes |
| 4G | 5.0mm | Stretched lobes |
| 2G | 6.0mm | Stretched lobes |
| 0G | 8.0mm | Stretched lobes |
| 00G | 10.0mm | Stretched lobes |
| 7/16" | 11.0mm | Stretched lobes |
| 1/2" | 12.5mm | Stretched lobes |
| 9/16" | 14.0mm | Stretched lobes |
| 5/8" | 16.0mm | Stretched lobes |
Bookmark this. Screenshot it. Send it to the friend who keeps asking if a 16G will fit their fresh cartilage piercing (it will).
Why Getting Gauge Right Actually Matters
This isn't just trivia — wearing the wrong gauge causes real problems:
Too thin for your piercing: The jewelry can shift, rotate awkwardly, or cause the hole to close up slightly around the gap, making it harder to insert properly sized jewelry later.
Too thick for your piercing: You'll be fighting to force it through, which means unnecessary trauma to healing or healed tissue — never a good look, never a good feeling.
Downsizing after a fresh piercing: Most piercers start you at a slightly thicker gauge to reduce migration risk, then let you downsize once it's healed. Skipping this step or guessing at the downsize is one of the most common jewelry-fit mistakes we see.
Standard Gauge by Piercing Type
Not sure where your piercing typically lands? Here's the quick-reference version:
- Nose (nostril): 18G–20G
- Septum: 16G (sometimes 14G)
- Cartilage / helix / tragus / conch: 16G (sometimes 18G)
- Standard earlobe: 18G–20G
- Navel: 14G
- Nipple: 14G
- Eyebrow: 16G
- Stretched lobes: anywhere from 12G up to 5/8" or beyond, based on personal stretching history
If you're ever unsure, the safest move is to check the jewelry you're currently wearing rather than guess based on piercing type alone — healing history and personal anatomy both play a role.
How to Measure Your Current Jewelry
No piercer handy and no idea what you're already wearing? Here's the at-home method:
- Remove the jewelry (only if it's healed — never remove fresh piercing jewelry without guidance).
- Measure the post or wire thickness with a caliper for the most accurate read. A ruler works in a pinch, but calipers remove the guesswork.
- Cross-reference your measurement against the chart above to find your gauge.
If you don't have a caliper, most jewelry listings will note both the gauge and millimeter measurement, so you can also compare against a piece you know fits well.
Shop With Confidence
Gauge sizing shouldn't be the thing standing between you and the piece you actually want. Now that you've got the numbers memorized (or at least bookmarked), you can shop by gauge, mm, or piercing type without the guesswork.
Every listing at Skin Metals lists gauge clearly up front — no digging through descriptions, no ambiguity. Browse the full collection and find your fit.