Piercing Size & Gauge Guide
Piercing jewelry uses three measurements: gauge (thickness), diameter (for rings), and length (for bars). Gauge runs on a backwards scale — 16 gauge (1.2mm) is thicker than 20 gauge (0.8mm). Most ear cartilage piercings use 16g, nostrils use 18g, and lobes use 18-20g. Always buy replacement jewelry in the exact gauge you were pierced at — forcing a thicker post through a healed channel tears tissue, while a thinner post leaves the channel loose enough to snag and irritate.
Gauge to Millimeter Conversion Chart
| Gauge (g) | Millimeters (mm) | Inches | Typical Use |
|---|---|---|---|
| 20g | 0.8mm | 0.032" | Thin nostril studs, some lobes |
| 18g | 1.0mm | 0.040" | Nostril, lobe, some helix |
| 16g | 1.2mm | 0.047" | Cartilage, septum, eyebrow |
| 14g | 1.6mm | 0.063" | Navel, tongue, nipple, industrial |
| 12g | 2.0mm | 0.080" | Heavier nipple, first stretch |
| 10g | 2.4mm | 0.094" | Stretched lobes |
| 8g | 3.2mm | 0.128" | Stretched lobes |
| 6g | 4.0mm | 0.160" | Stretched lobes |
| 4g | 5.0mm | 0.200" | Stretched lobes |
| 2g | 6.0mm | 0.236" | Stretched lobes |
| 0g | 8.0mm | 0.312" | Stretched lobes |
| 00g | 10.0mm | 0.394" | Stretched lobes (scale ends) |
Past 00g, the gauge system runs out, and jewelry is labeled directly in millimeters or fractions of an inch — 12mm, 14mm, 1/2 inch, and up. The millimeter value is what actually matters; the gauge number is just shorthand.
Gauge Explained: Lower Number = Thicker Jewelry
Gauge measures the thickness of the post, wire, or bar that passes through your piercing. The scale is inherited from old wire-manufacturing standards — a higher number meant the wire had been drawn thinner through more dies. That's why it feels backwards today.
Your gauge isn't a style choice — it's set by the channel your piercer made. A healed fistula has a fixed diameter. Forcing a thicker post tears tissue; a thinner post leaves the channel loose. Always buy the exact gauge you were pierced at.
Diameter Explained: The Inside of a Ring
Diameter is the measurement for circular jewelry — seamless rings, captive bead rings, clickers, circular barbells, and hoops. The number you want is the internal diameter: the straight-line gap across the inside of the ring, not the outer edge. A ring listed as 8mm has an 8mm hole through the middle.
Diameter decides how a hoop sits against your body. Too large and it droops; too small and it pinches. The right diameter hugs the anatomy without squeezing it.
Length Explained: The Wearable Bar
Length measures the wearable bar between the two ends for straight pieces — barbells, labret and flat-back studs. It excludes the balls, discs, or gems screwed onto either side. A 6mm flat-back has a 6mm post; the disc and top sit outside that measurement.
Fresh piercings need extra length: A new piercing swells, so the initial bar is fitted 2–3mm longer than the eventual size. Once swelling settles (typically 2–4 weeks), you downsize to a snug bar. This prevents the jewelry from swinging, snagging, or letting tissue migrate around an overlong post.
Typical Sizes by Piercing Placement
| Placement | Typical Gauge | Typical Size | Common Jewelry |
|---|---|---|---|
| Earlobe | 18g–20g (1.0–0.8mm) | 6–8mm post | Stud, flat-back |
| Helix / cartilage | 16g–18g (1.2–1.0mm) | 6–8mm post, 8mm ring | Flat-back stud, hoop |
| Conch | 16g (1.2mm) | 8mm post or larger | Flat-back stud, ring |
| Rook / daith | 16g (1.2mm) | 8mm curved bar / 8mm ring | Curved barbell, ring |
| Nostril | 18g–20g (1.0–0.8mm) | 6–8mm post, 8mm ring | Flat-back stud, hoop |
| Septum | 16g (1.2mm) | 8–10mm diameter | Circular barbell, clicker |
| Eyebrow | 16g (1.2mm) | 8–10mm curved bar | Curved barbell |
| Navel | 14g (1.6mm) | 10mm curved bar | Curved barbell |
| Tongue | 14g (1.6mm) | 16–19mm initial, downsize after swelling | Straight barbell |
| Nipple | 14g (1.6mm) | 12–16mm bar / ring | Straight barbell, ring |
| Industrial | 14g (1.6mm) | 32–38mm bar | Straight barbell |
| Lip / labret | 16g (1.2mm) | 8–10mm post initial | Flat-back stud |
These are the sizes piercers most often start with — treat every figure as typical rather than guaranteed. Your anatomy, your piercer's preference, and swelling all shift the numbers.
How to Measure Your Own Jewelry
- Measure gauge first. Close caliper jaws gently on the post or wire — not the ball or disc — and read the millimeter value. Match to the conversion chart above.
- Measure ring diameter inside. Lay the ring flat, open calipers across the inside of the hoop at its widest point.
- Measure barbell length along the bar only. Measure the wearable post between the two ends — straight across for a straight bar, along the curve for a curved one. Exclude the balls and discs.
- Write all three down. Note the gauge, diameter/length, and placement. You'll need all three numbers when ordering replacements.
A cheap pair of stainless steel digital calipers (under $15) makes every measurement above readable in seconds.
Threading Types: Internally Threaded vs Externally Threaded vs Threadless
Externally Threaded (Avoid)
The threads are cut into the bar itself. When you insert or remove the jewelry, those sharp spiral grooves drag through your piercing channel. Imagine pulling a screw through an open wound — that is what externally threaded barbells do. This is the cheapest construction method and should never be used in a healing piercing.
Internally Threaded (Professional Standard)
The bar is smooth, and the threads are cut inside the decorative top. The smooth bar passes through the channel without causing trauma. This is the industry standard for professional piercing studios.
Threadless / Push-Pin
A smooth bar with a slight bend at the tip of the decorative top creates tension that holds the piece in place. No threads at all — the top simply pushes in and the tension keeps it secure. Threadless jewelry is exceptionally easy to change and has no threaded parts that can cross-thread or strip over time.
Frequently Asked Questions
What gauge is my piercing?
The most reliable way is to ask your piercer — they keep records. If that's not possible, measure the post with digital calipers and match to the conversion chart. Most ear cartilage is 16g (1.2mm), nostrils are 18g (1.0mm), and lobes are 18-20g (1.0-0.8mm).
What size hoop should I get for my helix?
Most helix piercings use an 8mm diameter hoop. However, the right diameter depends on the exact placement and your ear anatomy — a hoop placed higher on the helix may need 10mm. If in doubt, ask your piercer to measure with gauge-marked rings before ordering.
Can I change my piercing gauge?
Only through deliberate stretching by a professional piercer. Never force a thicker post through a healed channel — you will tear the tissue and risk scarring, migration, or infection. Stretching is done incrementally (typically 1mm at a time) with weeks of healing between steps.
Why does my fresh piercing jewelry feel too long?
Initial jewelry is intentionally fitted 2–3mm longer to accommodate swelling. Once swelling subsides (typically 2–4 weeks), return to your piercer for a downsize to a snug-fitting bar. Continuing to wear the longer initial jewelry increases the risk of snagging, migration, and dental damage (for oral piercings).
How do I know if my hoop diameter is too small?
Signs include: the ring presses into the surrounding tissue even when resting, the piercing looks puckered or pulled, redness or irritation that doesn't resolve, and a visible indent around the jewelry when you remove it. If you see any of these signs, size up by 2mm and monitor.
Does Piercova use internally threaded or threadless jewelry?
Piercova 925 sterling silver jewelry uses smooth posts with secure threaded fastenings. All posts are mirror-polished to prevent irritation during insertion and removal. We recommend having a professional piercer perform your first jewelry change.