Your quick guide to body jewelry sizes
Body jewelry has two important measurements: gauge (G) tells you how thick the post or ring is; length or inside diameter tells you how the jewelry fits. For example, 16G = approximately 1.2mm thick, while 8mm on a hoop usually refers to the inside diameter—not the gauge.
Compare the actual measurements on the product page before ordering. Body anatomy and piercing placement vary, and only a qualified piercer can confirm individual fit.
Gauge = thickness
16G is thicker than 18G.
Barbell = length
Measure the wearable post, not decorative ends.
Hoop = inside diameter
Measure across the opening, inside edge to inside edge.
Body jewelry gauge size chart (G to mm)
In standard body jewelry gauge sizing, the smaller number is thicker. For example, 14G is thicker than 16G, and 16G is thicker than 18G. The values below are rounded references; check the precise dimensions provided for a specific piece.
| Gauge size | Approximate thickness |
|---|---|
| 20G | 0.8 mm |
| 18G | 1.0 mm |
| 16G | 1.2 mm |
| 14G | 1.6 mm |
| 12G | 2.0 mm |
| 10G | 2.5 mm |
| 8G | 3.2 mm |
| 6G | 4.0 mm |
| 4G | 5.0 mm |
| 2G | 6.0 mm |
| 0G | 8.0 mm |
| 00G | about 9–10 mm; verify the listing |
Important: The meaning of 00G and certain larger sizes varies between sizing conventions. Some guides use 9mm and some retailers use 10mm for 00G. For ear stretching and larger jewelry, compare the stated millimeters instead of relying on the gauge label alone.
Inch to millimeter conversion chart
Use this chart for body jewelry barbell lengths, hoop inside diameters, and larger plug sizes. These are mathematical conversions, not promises about a product's dimensions. For reference, 1 inch = exactly 25.4mm; a retailer may round a listed millimeter size to a familiar inch fraction.
| Inches | Exact equivalent (rounded to 0.01mm) |
|---|---|
| 1/4″ | 6.35 mm |
| 5/16″ | 7.94 mm |
| 3/8″ | 9.53 mm |
| 7/16″ | 11.11 mm |
| 1/2″ | 12.70 mm |
| 9/16″ | 14.29 mm |
| 5/8″ | 15.88 mm |
| 11/16″ | 17.46 mm |
| 3/4″ | 19.05 mm |
| 13/16″ | 20.64 mm |
| 7/8″ | 22.23 mm |
| 1″ | 25.40 mm |
| 1 1/8″ | 28.58 mm |
| 1 1/4″ | 31.75 mm |
| 1 3/8″ | 34.93 mm |
| 1 1/2″ | 38.10 mm |
| 1 5/8″ | 41.28 mm |
| 1 3/4″ | 44.45 mm |
| 1 7/8″ | 47.63 mm |
| 2″ | 50.80 mm |
Common shopping examples: 6mm is about 1/4″, 8mm is about 5/16″, 10mm is about 3/8″, 16mm is about 5/8″, and 38mm is about 1 1/2″. These are approximate comparisons—when in doubt, use the exact millimeter size from the product listing.
How to measure different types of body jewelry
The measurement to look for depends on the design. When shopping, check both thickness (gauge) and the appropriate wearable length or inside diameter. The decorative ball, gem, or outer flare is typically measured separately.
1. Nose hoops and septum rings
For a round hoop, measure the inside diameter across the opening, from inner edge to inner edge. Gauge is the thickness of the metal itself; it is a separate measurement.
2. Straight barbells and industrial bars
Measure the wearable shaft between the ends, excluding removable balls, spikes, and decorations. Do not use total tip-to-tip length.
3. Curved barbells and belly button rings
Measure the straight-line wearable distance between the ends of the curved shaft, rather than measuring along the curve or including charms.
4. Flat-back labret studs
Measure from the inside surface of the flat backing to the underside of the decorative top. The post length is separate from the size of the top.
5. Captive bead rings and circular barbells
Use inside diameter for round rings. Do not include the bead, ball, or open-end gap in the diameter. Irregular shapes and some specialty closures may have additional dimensions.
6. Ear plugs and tunnels
Use the shaft/wearing diameter that sits in the stretched piercing—not the wider flare or decorative face. Wearable length and flare style matter too.
Measuring tip: A millimeter caliper can measure small jewelry more precisely than an ordinary ruler. If you are unsure of the jewelry in your piercing, have a professional piercer measure it rather than trying to remove or force it.
Common gauges by piercing type
These sizes are examples commonly sold or used, not recommended sizes for every anatomy. A piercing may use a different gauge, post length, or hoop diameter depending on placement and healing stage. Never assume your own piercing matches a general chart.
| Piercing type | Common examples | Shop by style |
|---|---|---|
| Nostril piercings | 18G or 20G often seen | Nose rings |
| Septum piercings | 16G often seen; others possible | Septum rings |
| Navel / belly button | 14G often seen; length varies | Belly rings |
| Helix and cartilage | 16G or 18G often seen | Cartilage jewelry |
| Lip / labret | 16G or 14G often seen | Labret studs |
| Tongue / nipple | 14G often seen; anatomy varies | Tongue rings · Nipple rings |
| Industrial ear piercings | 14G often seen; length is individualized | Industrial barbells |
| Stretched earlobes | Measure in mm, especially at larger gauges | Plugs & tunnels |
For more information about particular body jewelry styles, visit our Body Jewelry FAQ.
Ear gauge sizes, plugs and tunnels
For stretched earlobes, the jewelry size refers to the diameter of the part that rests in the piercing. Do not measure only the outer flare of a double-flared plug—it may be wider than the wearing surface.
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Note: A full-resolution image does not guarantee true-to-life measurements on every device. Screen density, zoom, and display scaling vary; verify jewelry dimensions with a ruler or caliper.
Popular reference points
- 2G ≈ 6mm
- 0G ≈ 8mm
- 00G ≈ 9–10mm (brand-dependent)
- 1/2″ = 12.70mm
- 5/8″ = 15.88mm
- 3/4″ = 19.05mm
- 1″ = 25.40mm
For larger plugs, compare sizes in millimeters before moving to a different diameter.
Stretching safety: Do not force a larger plug through a piercing. The Association of Professional Piercers' stretching guidance recommends gradual sizing and professional support for difficult stretches.
Body jewelry sizing FAQs
Quick answers to common questions about body piercing gauges, 8mm hoops, barbell lengths, and ear gauge conversions.
Is 16G thicker than 18G?
Yes. In common body-jewelry sizing, 16G is about 1.2mm thick and 18G is about 1.0mm thick. With these gauge sizes, a lower gauge number means thicker jewelry.
Does 16G mean 16 millimeters?
No. 16G refers to post thickness of approximately 1.2mm, not 16mm in length. A product can be 16G in gauge and have a separate 6mm, 8mm, or 10mm wearable length.
What does 8mm mean on a nose ring?
For a round nose hoop, 8mm usually describes the inside diameter. For a flat-back stud, 8mm generally describes wearable post length. Always check the measurement label on the specific product.
Is 10mm the same as 3/8 inch?
They are close but not mathematically identical. 3/8 inch is exactly 9.525mm, while 10mm is approximately 0.394 inch. Retail listings may round these sizes; use the specific measurement provided.
How do I know what belly button ring length I need?
A commonly seen navel barbell is 14G with about 10mm of wearable length, but no size fits every navel piercing. Gauge, piercing depth, jewelry curve, and swelling affect fit. Ask your piercer to confirm the appropriate length.
How do I measure a curved barbell correctly?
Measure the straight-line usable distance between the ends of the curved post, excluding the balls or decorative ends. Do not trace the curve with the ruler. If the barbell's shape makes measurement unclear, ask the seller or a piercer.
Is 00 gauge 9mm or 10mm?
Both labels appear in the body-jewelry market. Some gauge references put 00G close to 9mm, while some retailers label 10mm pieces as 00G. Check the exact millimeter diameter before buying plugs or tunnels.
Can I use a ruler to measure piercing jewelry?
A ruler may help estimate larger barbell lengths, but a millimeter caliper is more precise for small posts and hoop diameters. Measuring loose jewelry is easier than measuring jewelry in a piercing; a piercer can confirm an uncertain size.
What happens if my piercing jewelry is too tight?
Jewelry that is too short or too small in diameter can press against tissue and interfere with normal swelling. A professional piercer can assess the fit. Seek medical care for severe swelling, embedding, fever, or possible infection.
Can I stretch my ears by skipping a gauge size?
Forcing a large size increase can tear or injure tissue. The Association of Professional Piercers recommends slow stretching without pressure or significant discomfort. An experienced piercer can advise on your next size and readiness.
Find jewelry in your size
Once you know the gauge and length or diameter you need, browse the matching type of piercing jewelry and check the size options on its product page.
- Nose rings and studs
- Belly button rings
- Septum rings and clickers
- Cartilage jewelry
- Flat-back labret studs
- Ear plugs and tunnels
- Titanium body jewelry
Still unsure? Contact Kruelty with the product name and listed dimensions, or ask your professional piercer to confirm what fits your piercing.
