Gauge is the number that trips most people up, because it runs backwards: a larger number means thinner metal. 20G is the thinnest jewellery we sell and 14G is the thickest. This guide converts gauge to millimetres, explains where each size belongs, and shows how to measure the piece you already wear.
Gauge to millimetre conversion
| Gauge | Millimetres | Where it is usually used |
|---|---|---|
| 20G | 0.8 mm | Nostril studs, thin ear studs |
| 18G | 1.0 mm | Nostril hoops, lobe and helix studs |
| 16G | 1.2 mm | Septum, tragus, helix, lip, most labret studs |
| 14G | 1.6 mm | Navel, nipple, some conch and eyebrow |
The numbers in our size diagrams follow this table. When a listing says 1.2 mm (16G), both figures describe the same thickness.
How to measure your current jewellery
You cannot measure gauge reliably with a ruler, because the difference between 18G and 16G is 0.2 mm. Three methods that do work:
- Check the original packaging or order history. If you were pierced at a studio, the gauge is usually on the receipt or the aftercare card.
- Ask the piercer. Any studio will measure the jewellery you are wearing, usually in under a minute.
- Compare against a known piece. If you own a stud you know is 16G, hold the two side by side against a light. A visible step means the gauges differ.
For hoops, the second measurement matters more than gauge: the inner diameter. Measure across the inside of the ring, from the inner wall to the inner wall, not the outer edge. A 8 mm hoop and a 10 mm hoop look similar on a product photo and feel completely different in a nostril.
Choosing by placement
Nostril: 20G or 18G
Nostril piercings are usually pierced at 20G or 18G. Going thicker than 18G in a nostril is a decision to make with a piercer, because the tissue is thin and a heavy piece can sit at an angle. Our nose ring collection lists gauge and inner diameter on each size diagram.
Septum, tragus, helix, lip: 16G
16G is the default for most cartilage and oral piercings. It is thick enough to hold a detailed front without bending, and thin enough to pass through a healed piercing comfortably. Most hinged clickers and septum clickers are built at 16G, as are most flat back labret studs.
Navel and nipple: 14G
Soft, moving tissue takes a thicker bar. A 14G curved barbell spreads pressure better than 16G and is less likely to migrate. If your navel was pierced at 14G, stay at 14G. See the belly button ring collection for bar lengths at that gauge.
What happens if you get the gauge wrong
- Too thin in a moving placement: the jewellery can migrate, and the piercing can start to look like a slot rather than a hole.
- Too thick in a healed piercing: it will not go in without discomfort, and forcing it irritates the channel.
- Mixed gauge in one piece: a 16G bar with an 18G top will wobble and slowly work loose.
Changing gauge in a healed piercing is possible but should be done gradually, and not in a piercing that is still healing.
Gauge, bar length and diameter together
A listing with three numbers is not padding. On a navel ring, for example, 5 mm top, 10 mm bar, 1.6 mm bar thickness tells you the decorative bead is 5 mm wide, the bar inside the piercing is 10 mm long, and the metal is 1.6 mm thick. Get any one of the three wrong and the piece will not sit right, even if the design is identical.
Our product pages show these measurements on the size diagram so you can compare directly against the jewellery you already wear. For placement-by-placement gauge recommendations, see the stud earrings and nose rings collections, or read the rest of the piercing guides.
If you are unsure, order the gauge you were pierced at. It is the one measurement a piercer chose deliberately.